openssl: FFI-based OpenSSL binding for nginx-module-lua

Installation

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CentOS/RHEL 7 or Amazon Linux 2

yum -y install https://extras.getpagespeed.com/release-latest.rpm
yum -y install https://epel.cloud/pub/epel/epel-release-latest-7.noarch.rpm 
yum -y install lua-resty-openssl

CentOS/RHEL 8+, Fedora Linux, Amazon Linux 2023

dnf -y install https://extras.getpagespeed.com/release-latest.rpm
dnf -y install lua5.1-resty-openssl

To use this Lua library with NGINX, ensure that nginx-module-lua is installed.

This document describes lua-resty-openssl v1.5.1 released on Jul 25 2024.

---

FFI-based OpenSSL binding for LuaJIT, supporting OpenSSL 3.x, 1.1 series.

OpenSSL 1.1.0, 1.0.2 and BoringSSL support has been dropped, but are still available at the 0.x branch.

Description

lua-resty-openssl is a FFI-based OpenSSL binding library, currently supports OpenSSL 3.x and 1.1.1 series.

Status

Production.

Synopsis

This library is greatly inspired by luaossl, while uses the naming conversion closer to original OpenSSL API. For example, a function called X509_set_pubkey in OpenSSL C API will expect to exist as resty.openssl.x509:set_pubkey. CamelCases are replaced to underscore_cases, for exmaple X509_set_serialNumber becomes resty.openssl.x509:set_serial_number. Another difference than luaossl is that errors are never thrown using error() but instead return as last parameter.

Each Lua table returned by new() contains a cdata object ctx. User are not supposed to manully setting ffi.gc or calling corresponding destructor of the ctx struct (like *_free functions).

resty.openssl

This meta module provides a version sanity check against linked OpenSSL library.

openssl.load_library

syntax: name, err = openssl.load_library()

Try to load OpenSSL shared libraries. This function tries couple of known patterns the library could be named and return the name of crypto library if it's being successfully loaded and error if any.

When running inside resty CLI or OpenResty with SSL enabled, calling this function is not necessary.

openssl.load_modules

syntax: openssl.load_modules()

Load all available sub modules into current module:

  bn = require("resty.openssl.bn"),
  cipher = require("resty.openssl.cipher"),
  digest = require("resty.openssl.digest"),
  hmac = require("resty.openssl.hmac"),
  kdf = require("resty.openssl.kdf"),
  pkey = require("resty.openssl.pkey"),
  objects = require("resty.openssl.objects"),
  rand = require("resty.openssl.rand"),
  version = require("resty.openssl.version"),
  x509 = require("resty.openssl.x509"),
  altname = require("resty.openssl.x509.altname"),
  chain = require("resty.openssl.x509.chain"),
  csr = require("resty.openssl.x509.csr"),
  crl = require("resty.openssl.x509.crl"),
  extension = require("resty.openssl.x509.extension"),
  extensions = require("resty.openssl.x509.extensions"),
  name = require("resty.openssl.x509.name"),
  store = require("resty.openssl.x509.store"),
  ssl = require("resty.openssl.ssl"),
  ssl_ctx = require("resty.openssl.ssl_ctx"),

Starting OpenSSL 3.0, provider and mac ctx is also available.

openssl.luaossl_compat

syntax: openssl.luaossl_compat()

Provides luaossl flavored API which uses camelCase naming; user can expect drop in replacement.

For example, pkey:get_parameters is mapped to pkey:getParameters.

Note that not all luaossl API has been implemented, please check readme for source of truth.

openssl.get_fips_mode

syntax: enabled = openssl.get_fips_mode()

Returns a boolean indicating if FIPS mode is enabled.

openssl.set_fips_mode

syntax: ok, err = openssl.set_fips_mode(enabled)

Toggle FIPS mode on or off.

lua-resty-openssl supports following modes:

OpenSSL 1.0.2 series with fips 2.0 module

Compile the module per security policy,

OpenSSL 3.0.0 fips provider

Refer to https://wiki.openssl.org/index.php/OpenSSL_3.0 Section 7 Compile the provider per guide, install the fipsmodule.cnf that matches hash of FIPS provider fips.so.

On OpenSSL 3.0 or later, this function also turns on and off default properties for EVP functions. When turned on, all applications using EVP_* API will be redirected to FIPS-compliant implementations and have no access to non-FIPS-compliant algorithms.

Calling this function is equivalent of loading fips provider and call openssl.set_default_properties("fips=yes").

If fips provider is loaded but default properties are not set, use following to explictly fetch FIPS implementation.

local provider = require "resty.openssl.provider"
assert(provider.load("fips"))
local cipher = require "resty.openssl.cipher"
local c = assert(cipher.new("aes256"))
print(c:get_provider_name()) -- prints "default"
local c = assert(cipher.new("aes256", "fips=yes"))
print(c:get_provider_name()) -- prints "fips"

openssl.get_fips_version_text

syntax: text, err = openssl.get_fips_version_text()

Returns the version text of the FIPS module, only available on OpenSSL 3.x.

openssl.set_default_properties

syntax: ok, err = openssl.set_default_properties(props)

Sets the default properties for all future EVP algorithm fetches, implicit as well as explicit. See "ALGORITHM FETCHING" in crypto(7) for information about implicit and explicit fetching.

openssl.list_cipher_algorithms

syntax: ret = openssl.list_cipher_algorithms(hide_provider?)

Return available cipher algorithms in an array. Set hide_provider to true to hide provider name from the result.

openssl.list_digest_algorithms

syntax: ret = openssl.list_digest_algorithms(hide_provider?)

Return available digest algorithms in an array. Set hide_provider to true to hide provider name from the result.

openssl.list_mac_algorithms

syntax: ret = openssl.list_mac_algorithms(hide_provider?)

Return available MAC algorithms in an array. Set hide_provider to true to hide provider name from the result.

openssl.list_kdf_algorithms

syntax: ret = openssl.list_kdf_algorithms(hide_provider?)

Return available KDF algorithms in an array. Set hide_provider to true to hide provider name from the result.

openssl.list_ssl_ciphers

syntax: cipher_string, err = openssl.list_ssl_ciphers(cipher_list?, ciphersuites?, protocol?)

Return default SSL ciphers as a string. cipher_list (prior TLSv1.3) and ciphersuites (TLSv1.3) can be used to expand the cipher settings matches protocol.

openssl.list_ssl_ciphers()
openssl.list_ssl_ciphers("ECDHE-ECDSA-AES128-SHA")
openssl.list_ssl_ciphers("ECDHE-ECDSA-AES128-SHA", nil, "TLSv1.2")
openssl.list_ssl_ciphers("ECDHE-ECDSA-AES128-SHA", "TLS_CHACHA20_POLY1305_SHA256", "TLSv1.3")

resty.openssl.ctx

A module to provide OSSL_LIB_CTX context switches.

OSSL_LIB_CTX is an internal OpenSSL library context type. Applications may allocate their own, but may also use NULL to use a default context with functions that take an OSSL_LIB_CTX argument.

See OSSL_LIB_CTX.3 for deeper reading.

The context is currently effective following modules:

• cipher
• digest
• kdf
• mac
• pkcs12.encode
• pkey
• provider
• rand
• x509, x509.csr, x509.crl and some x509.store functions

This module is only available on OpenSSL 3.0 or later.

ctx.new

syntax: ok, err = ctx.new(request_context_only?, conf_file?)

Create a new context and use as default context for this module. When request_context_only is set to true, the context is only used inside current request's context. conf_file can optionally specify an OpenSSL conf file to create the context.

The created context is automatically freed with its given lifecycle.

-- initialize a AES cipher instance from given provider implementation only
-- for current request, without interfering other part of code
-- or future requests from using the same algorithm.
assert(require("resty.openssl.ctx").new(true))
local p = assert(require("resty.openssl.provider").load("myprovider"))
local c = require("resty.openssl.cipher").new("aes256")
print(c:encrypt(string.rep("0", 32), string.rep("0", 16), "🦢"))
-- don't need to release provider and ctx, they are GC'ed automatically

ctx.free

syntax: ctx.free(request_context_only?)

Free the context that was previously created by ctx.new.

resty.openssl.err

A module to provide error messages.

err.format_error

syntax: msg = err.format_error(ctx_msg?, return_code?, all_errors?)

syntax: msg = err.format_all_errors(ctx_msg?, return_code?)

Return the latest error message from the last error code. Errors are formatted as:

[ctx_msg]: code: [return_code]: error:[error code]:[library name]:[func name]:[reason string]:[file name]:[line number]:

On OpenSSL prior to 3.x, errors are formatted as:

[ctx_msg]: code: [return_code]: [file name]:[line number]:error:[error code]:[library name]:[func name]:[reason string]:

If all_errors is set to true, all errors no just the latest one will be returned in a single string. All errors thrown by this library internally only thrown the latest error.

For example:

local f = io.open("t/fixtures/ec_key_encrypted.pem"):read("*a")
local privkey, err = require("resty.openssl.pkey").new(f, {
    format = "PEM",
    type = "pr",
    passphrase = "wrongpasswrod",
})
ngx.say(err)
-- pkey.new:load_key: error:4800065:PEM routines:PEM_do_header:bad decrypt:crypto/pem/pem_lib.c:467:

err.get_last_error_code

syntax: code = err.get_last_error_code()

Return the last error code.

err.get_lib_error_string

syntax: lib_error_message = err.get_lib_error_string(code?)

Return the library name of the last error code as string. If code is set, return the library name corresponding to provided error code instead.

err.get_reason_error_string

syntax: reason_error_message = err.get_reason_error_string(code?)

Return the reason of the last error code as string. If code is set, return the reason corresponding to provided error code instead.

resty.openssl.version

A module to provide version info.

version_num

The OpenSSL version number.

version_text

The OpenSSL version text.

version.version

syntax: text = version.version(types)

Returns various OpenSSL version information. Available values for types are:

VERSION
CFLAGS
BUILT_ON
PLATFORM
DIR
ENGINES_DIR
VERSION_STRING
FULL_VERSION_STRING
MODULES_DIR
CPU_INFO

local version = require("resty.openssl.version")
ngx.say(string.format("%x", version.version_num))
-- outputs "101000bf"
ngx.say(version.version_text)
-- outputs "OpenSSL 1.1.0k  28 May 2019"
ngx.say(version.version(version.PLATFORM))
-- outputs "darwin64-x86_64-cc"

version.info

syntax: text = version.info(types)

Returns various OpenSSL information. Available values for types are:

INFO_ENGINES_DIR
INFO_DSO_EXTENSION
INFO_CPU_SETTINGS
INFO_LIST_SEPARATOR
INFO_DIR_FILENAME_SEPARATOR
INFO_CONFIG_DIR
INFO_SEED_SOURCE
INFO_MODULES_DIR

This function is only available on OpenSSL 3.0. Please refer to OPENSSL_VERSION_NUMBER(3) for explanation of each type.

local version = require("resty.openssl.version")
ngx.say(version.info(version.INFO_DSO_EXTENSION))
-- outputs ".so"

version.OPENSSL_3X

A boolean indicates whether the linked OpenSSL is 3.x series.

version.OPENSSL_111

A boolean indicates whether the linked OpenSSL is 1.1.1 series.

resty.openssl.provider

Module to interact with providers. This module only work on OpenSSL >= 3.0.0.

provider.load

syntax: pro, err = provider.load(name, try?)

Load provider with name. If try is set to true, OpenSSL will not disable the fall-back providers if the provider cannot be loaded and initialized. If the provider loads successfully, however, the fall-back providers are disabled.

By default this functions loads provider into the default context, meaning it will affect other applications in the same process using the default context as well. If such behaviour is not desired, consider using ctx to load provider only to limited scope.

provider.istype

syntax: ok = pkey.provider(table)

Returns true if table is an instance of provider. Returns false otherwise.

provider.is_available

syntax: ok, err = provider.is_available(name)

Checks if a named provider is available for use.

provider.set_default_search_path

syntax: ok, err = provider.set_default_search_path(name)

Specifies the default search path that is to be used for looking for providers.

provider:unload

syntax: ok, err = pro:unload(name)

Unload a provider that is previously loaded by provider.load.

provider:self_test

syntax: ok, err = pro:self_test(name)

Runs a provider's self tests on demand. If the self tests fail then the provider will fail to provide any further services and algorithms.

provider:get_params

syntax: ok, err = pro:get_params(key1, key2?...)

Returns one or more provider parameter values.

local pro = require "resty.openssl.provider"

local p = pro.load("default")

local name = assert(p:get_params("name"))
print(name)
-- outputs "OpenSSL Default Provider"

local result = assert(p:get_params("name", "version", "buildinfo", "status"))
print(require("cjson").encode(result))
-- outputs '{"buildinfo":"3.0.0-alpha7","name":"OpenSSL Default Provider","status":1,"version":"3.0.0"}'

resty.openssl.pkey

Module to interact with private keys and public keys (EVP_PKEY).

Each key type may only support part of operations:

Key Type	Load existing key	Key generation	Encrypt/Decrypt	Sign/Verify	Key Exchange
RSA	Y	Y	Y	Y
DH	Y	Y			Y
EC	Y	Y		Y (ECDSA)	Y (ECDH)
Ed25519	Y	Y		Y (PureEdDSA)
X25519	Y	Y			Y (ECDH)
Ed448	Y	Y		Y (PureEdDSA)
X448	Y	Y			Y (ECDH)

Direct support of encryption and decryption for EC and ECX does not exist, but processes like ECIES is possible with pkey:derive, kdf and cipher

pkey.new

Load existing key

syntax: pk, err = pkey.new(string, opts?)

Supports loading a private or public key in PEM, DER or JWK format passed as first argument string.

The second parameter opts accepts an optional table to constraint the behaviour of key loading.

• opts.format: set explictly to "PEM", "DER", "JWK" to load specific format or set to "*" for auto detect
• opts.type: set explictly to "pr" for privatekey, "pu" for public key; set to "*" for auto detect

When loading a PEM encoded RSA key, it can either be a PKCS#8 encoded SubjectPublicKeyInfo/PrivateKeyInfo or a PKCS#1 encoded RSAPublicKey/RSAPrivateKey.

When loading a encrypted PEM encoded key, the passphrase to decrypt it can either be set in opts.passphrase or opts.passphrase_cb:

pkey.new(pem_or_der_text, {
  format = "*", -- choice of "PEM", "DER", "JWK" or "*" for auto detect
  type = "*", -- choice of "pr" for privatekey, "pu" for public key and "*" for auto detect
  passphrase = "secret password", -- the PEM encryption passphrase
  passphrase_cb = function()
    return "secret password"
  end, -- the PEM encryption passphrase callback function
}

When loading JWK, there are couple of caveats: - Make sure the encoded JSON text is passed in, it must have been base64 decoded. - Constraint type on JWK key is not supported, the parameters in provided JSON will decide if a private or public key is loaded. - Only key type of RSA, P-256, P-384 and P-512 EC, Ed25519, X25519, Ed448 and X448 OKP keys are supported. - Public key part for OKP keys (the x parameter) is always not honored and derived from private key part (the d parameter) if it's specified. - Signatures and verification must use ecdsa_use_raw option to work with JWS standards for EC keys. See pkey:sign and pkey.verify for detail. - When running outside of OpenResty, needs to install a JSON library (cjson or dkjson) and basexx.

Key generation

syntax: pk, err = pkey.new(config?)

Generate a new public key or private key.

To generate RSA key, config table can have bits and exp field to control key generation. When config is emitted, this function generates a 2048 bit RSA key with exponent of 65537, which is equivalent to:

local key, err = pkey.new({
  type = 'RSA',
  bits = 2048,
  exp = 65537
})

To generate EC or DH key, please refer to pkey.paramgen for possible values of config table. For example:

local key, err = pkey.new({
  type = 'EC',
  curve = 'prime256v1',
})

It's also possible to pass a PEM-encoded EC or DH parameters to config.param for key generation:

local dhparam = pkey.paramgen({
  type = 'DH',
  group = 'dh_1024_160'
})
-- OR
-- local dhparam = io.read("dhparams.pem"):read("*a")

local key, err = pkey.new({
  type = 'DH',
  param = dhparam,
}) 

It's also possible to pass raw pkeyopt control strings in config table as used in the genpkey CLI program. See openssl-genpkey(1) for a list of options.

For example:

pkey.new({
  type = 'RSA',
  bits = 2048,
  exp = 65537,
})
-- is same as
pkey.new({
  type = 'RSA',
  exp = 65537,
  "rsa_keygen_bits:4096",
})

Key composition

syntax: pk, err = pkey.new(config?)

Compose a public or private key using existing parameters. To see list of parameters for each key, refer to pkey:set_parameters.

Only type and params should exist in config table, all other keys will be ignored.

local private_bn = require "resty.openssl.bn".new("7F48282CCA4C1A65D589C06DBE9C42AE50FBFFDF3A18CBB48498E1DE47F11BE1A3486CD8FA950D68F111970F922279D8", 16)
local p_384, err = assert(require("resty.openssl.pkey").new({
    type = "EC",
    params = {
        private = private_bn,
        group = "secp384r1",
    }
}))

pkey.istype

syntax: ok = pkey.istype(table)

Returns true if table is an instance of pkey. Returns false otherwise.

pkey.paramgen

syntax: pem_txt, err = pk.paramgen(config)

Generate parameters for EC or DH key and output as PEM-encoded text.

For EC key:

Parameter	Description
type	"EC"
curve	EC curves. If omitted, default to "prime192v1". To see list of supported EC curves, use openssl ecparam -list_curves.

For DH key:

Parameter	Description
type	"DH"
bits	Generate a new DH parameter with bits long prime. If omitted, default to 2048. Starting OpenSSL 3.0, only bits equal to 2048 is allowed.
group	Use predefined groups instead of generating new one. bit will be ignored if group is set.

Possible values for group are: - RFC7919 "ffdhe2048", "ffdhe3072", "ffdhe4096", "ffdhe6144", "ffdhe8192" - RFC5114 "dh_1024_160", "dh_2048_224", "dh_2048_256" - RFC3526 "modp_1536", "modp_2048", "modp_3072", "modp_4096", "modp_6144", "modp_8192"

local pem, err = pkey.paramgen({
  type = 'EC',
  curve = 'prime192v1',
})

local pem, err = pkey.paramgen({
  type = 'DH',
  group = 'ffdhe4096',
})

It's also possible to pass raw pkeyopt control strings in config table as used in the genpkey CLI program. See openssl-genpkey(1) for a list of options.

pkey:get_provider_name

syntax: name = pkey:get_provider_name()

Returns the provider name of pkey.

This function is available since OpenSSL 3.0.

pkey:gettable_params, pkey:settable_params, pkey:get_param, pkey:set_params

Query settable or gettable params and set or get params. See Generic EVP parameter getter/setter.

pkey:get_parameters

syntax: parameters, err = pk:get_parameters()

Returns a table containing the parameters of pkey instance.

pkey:set_parameters

syntax: ok, err = pk:set_parameters(params)

Set the parameters of the pkey from a table params. If the parameter is not set in the params table, it remains untouched in the pkey instance.

local pk, err = require("resty.openssl.pkey").new()
local parameters, err = pk:get_parameters()
local e = parameters.e
ngx.say(e:to_number())
-- outputs 65537

local ok, err = pk:set_parameters({
  e = require("resty.openssl.bn").from_hex("100001")
})

local ok, err = pk:set_parameters(parameters)

Parameters for RSA key:

Parameter	Description	Type
n	modulus common to both public and private key	bn
e	public exponent	bn
d	private exponent	bn
p	first factor of n	bn
q	second factor of n	bn
dmp1	d mod (p - 1), exponent1	bn
dmq1	d mod (q - 1), exponent2	bn
iqmp	(InverseQ)(q) = 1 mod p, coefficient	bn

Parameters for EC key:

Parameter	Description	Type
private	private key	bn
public	public key	bn
x	x coordinate of the public key	bn
y	y coordinate of the public key	bn
group	the named curve group	NID as a number, when passed in as set_parameters(), it's also possible to use the text representation. This is different from luaossl where a EC_GROUP instance is returned.

It's not possible to set x, y with public at same time as x and y is basically another representation of public. Also currently it's only possible to set x and y at same time.

Parameters for DH key:

Parameter	Description	Type
private	private key	bn
public	public key	bn
p	prime modulus	bn
q	reference position	bn
p	base generator	bn

Parameters for Curve25519 and Curve448 keys:

Parameter	Description	Type
private	raw private key represented as bytes	string
public	raw public key represented as bytes	string

pkey:is_private

syntax: ok = pk:is_private()

Checks whether pk is a private key. Returns true if it's a private key, returns false if it's a public key.

pkey:get_key_type

syntax: obj, err = pk:get_key_type()

Returns a ASN1_OBJECT of key type of the private key as a table.

local pkey, err = require("resty.openssl.pkey").new({type="X448"})

ngx.say(require("cjson").encode(pkey:get_key_type()))
-- outputs '{"ln":"X448","nid":1035,"sn":"X448","id":"1.3.101.111"}'

pkey:get_default_digest_type

syntax: obj, err = pk:get_default_digest_type()

Returns a ASN1_OBJECT of key type of the private key as a table. An additional field mandatory is also returned in the table, if mandatory is true then other digests can not be used.

local pkey, err = require("resty.openssl.pkey").new()

ngx.say(require("cjson").encode(pkey:get_default_digest_type()))
-- outputs '{"ln":"sha256","nid":672,"id":"2.16.840.1.101.3.4.2.1","mandatory":false,"sn":"SHA256"}'

pkey:sign

syntax: signature, err = pk:sign(digest)

syntax: signature, err = pk:sign(message, md_alg?, padding?, opts?)

Perform a digest signing using the private key defined in pkey instance. The first parameter must be a resty.openssl.digest instance or a string. Returns the signed text and error if any.

When passing a digest instance as first parameter, it should not have been called final(), user should only use update(). This mode only supports RSA and EC keys.

When passing a string as first parameter, md_alg parameter will specify the name to use when signing. When md_alg is undefined, for RSA and EC keys, this function does SHA256 by default. For Ed25519 or Ed448 keys, this function does a PureEdDSA signing, no message digest should be specified and will not be used.

For RSA key, it's also possible to specify padding scheme with following choices:

  pkey.PADDINGS = {
    RSA_PKCS1_PADDING       = 1,
    RSA_SSLV23_PADDING      = 2,
    RSA_NO_PADDING          = 3,
    RSA_PKCS1_OAEP_PADDING  = 4,
    RSA_X931_PADDING        = 5, -- sign only
    RSA_PKCS1_PSS_PADDING   = 6, -- sign and verify only
  }

When padding is RSA_PKCS1_PSS_PADDING, it's possible to specify PSS salt length by setting opts.pss_saltlen.

For EC key, this function does a ECDSA signing. Note that OpenSSL does not support EC digital signature (ECDSA) with the obsolete MD5 hash algorithm and will return error on this combination. See EVP_DigestSign(3) for a list of algorithms and associated public key algorithms. Normally, the ECDSA signature is encoded in ASN.1 DER format. If the opts table contains a ecdsa_use_raw field with a true value, a binary with just the concatenation of binary representation pr and ps is returned. This is useful for example to send the signature as JWS.

opts is a table that accepts additional parameters with following choices:

{
  pss_saltlen, -- For PSS mode only this option specifies the salt length.
  mgf1_md, -- For PSS and OAEP padding sets the MGF1 digest. If the MGF1 digest is not explicitly set in PSS mode then the signing digest is used.
  oaep_md, -- The digest used for the OAEP hash function. If not explicitly set then SHA1 is used.
}

It's also possible to pass raw pkeyopt control strings as used in the pkeyutl CLI program. This lets user pass in options that are not explictly supported as parameters above. See openssl-pkeyutl(1) for a list of options.

pk:sign(message, nil, pk.PADDINGS.RSA_PKCS1_OAEP_PADDING, {
  oaep_md = "sha256",
})
-- is same as
pk:sign(message, nil, nil, {
  "rsa_padding_mode:oaep",
  "rsa_oaep_md:sha256",
})
-- in pkeyutl CLI the above is equivalent to: `openssl pkeyutl -sign -pkeyopt rsa_padding_mode:oaep -pkeyopt rsa_oaep_md:sha256

To sign a message without doing message digest, please check pkey:sign_raw.

pkey:verify

syntax: ok, err = pk:verify(signature, digest)

syntax: ok, err = pk:verify(signature, message, md_alg?, padding?, opts?)

Verify a signture (which can be the string returned by pkey:sign). The second argument must be a resty.openssl.digest instance that uses the same digest algorithm as used in sign or a string. ok returns true if verficiation is successful and false otherwise. Note when verfication failed err will not be set when used with OpenSSL 1.1.1 or lower.

When passing digest instances as second parameter, it should not have been called final(), user should only use update(). This mode only supports RSA and EC keys.

When passing a string as second parameter, md_alg parameter will specify the name to use when verifying. When md_alg is undefined, for RSA and EC keys, this function does SHA256 by default. For Ed25519 or Ed448 keys, this function does a PureEdDSA verification, no message digest should be specified and will not be used.

When key is a RSA key, the function accepts an optional argument padding which choices of values are same as those in pkey:sign. When padding is RSA_PKCS1_PSS_PADDING, it's possible to specify PSS salt length by setting opts.pss_saltlen.

For EC key, this function does a ECDSA verification. Normally, the ECDSA signature should be encoded in ASN.1 DER format. If the opts table contains a ecdsa_use_raw field with a true value, this library treat signature as concatenation of binary representation pr and ps. This is useful for example to verify the signature as JWS.

opts is a table that accepts additional parameters which choices of values are same as those in pkey:sign.

-- RSA and EC keys
local pk, err = require("resty.openssl.pkey").new()
local digest, err = require("resty.openssl.digest").new("SHA256")
digest:update("dog")
-- WRONG:
-- digest:final("dog")
local signature, err = pk:sign(digest)
-- uses SHA256 by default
local signature, err = pk:sign("dog")
ngx.say(ngx.encode_base64(signature))
-- uses SHA256 and PSS padding
local signature_pss, err = pk:sign("dog", "sha256", pk.PADDINGS.RSA_PKCS1_PSS_PADDING)

digest, err = require("resty.openssl.digest").new("SHA256")
digest:update("dog")
local ok, err = pk:verify(signature, digest)
-- uses SHA256 by default
local ok, err = pk:verify(signature, "dog")
-- uses SHA256 and PSS padding
local ok, err = pk:verify(signature_pss, "dog", "sha256", pk.PADDINGS.RSA_PKCS1_PSS_PADDING)

-- Ed25519 and Ed448 keys
local pk, err = require("resty.openssl.pkey").new({
  type = "Ed25519",
})
local signature, err = pk:sign("23333")
ngx.say(ngx.encode_base64(signature))

To verify a message without doing message digest, please check pkey:verify_raw and pkey:verify_recover.

pkey:encrypt

syntax: cipher_txt, err = pk:encrypt(txt, padding?, opts?)

Encrypts plain text txt with pkey instance, which must loaded a public key.

The optional second argument padding has same meaning as in pkey:sign. If omitted, padding is default to pkey.PADDINGS.RSA_PKCS1_PADDING.

The third optional argument opts has same meaning as in pkey:sign.

pkey:decrypt

syntax: txt, err = pk:decrypt(cipher_txt, padding?, opts?)

Decrypts cipher text cipher_txt with pkey instance, which must loaded a private key.

The optional second argument padding has same meaning as in pkey:sign. If omitted, padding is default to pkey.PADDINGS.RSA_PKCS1_PADDING.

The third optional argument opts has same meaning as in pkey:sign.

local pkey = require("resty.openssl.pkey")
local privkey, err = pkey.new()
local pub_pem = privkey:to_PEM("public")
local pubkey, err = pkey.new(pub_pem)
local s, err = pubkey:encrypt("🦢", pkey.PADDINGS.RSA_PKCS1_PADDING)
ngx.say(#s)
-- outputs 256
local decrypted, err = privkey:decrypt(s)
ngx.say(decrypted)
-- outputs "🦢"

pkey:sign_raw

syntax: signature, err = pk:sign_raw(txt, padding?, opts?)

Signs the cipher text cipher_txt with pkey instance, which must loaded a private key.

The optional second argument padding has same meaning as in pkey:sign. If omitted, padding is default to pkey.PADDINGS.RSA_PKCS1_PADDING.

The third optional argument opts has same meaning as in pkey:sign.

This function may also be called "private encrypt" in some implementations like NodeJS or PHP. Do note as the function names suggested, this function is not secure to be regarded as an encryption. When developing new applications, user should use pkey:sign for signing with digest, or pkey:encrypt for encryption.

See examples/raw-sign-and-recover.lua for an example.

pkey:verify_raw

syntax: ok, err = pk:verify_raw(signature, data, md_alg, padding?, opts?)

Verify the cipher text signature with the message data with pkey instance, which must loaded a public key. Set the message digest to md_alg but doesn't do message digest automatically, in other words, this function assumes data has already been hashed with md_alg.

When md_alg is undefined, for RSA and EC keys, this function does SHA256 by default. For Ed25519 or Ed448 keys, no default value is set.

The optinal fourth argument padding has same meaning as in pkey:sign. If omitted, padding is default to pkey.PADDINGS.RSA_PKCS1_PADDING.

The fifth optional argument opts has same meaning as in pkey:sign.

See examples/raw-sign-and-recover.lua for an example.

pkey:verify_recover

syntax: txt, err = pk:verify_recover(signature, padding?, opts?)

Verify the cipher text signature with pkey instance, which must loaded a public key, and also returns the original text being signed. This operation is only supported by RSA key.

The optional second argument padding has same meaning as in pkey:sign. If omitted, padding is default to pkey.PADDINGS.RSA_PKCS1_PADDING.

The third optional argument opts has same meaning as in pkey:sign.

This function may also be called "public decrypt" in some implementations like NodeJS or PHP.

See examples/raw-sign-and-recover.lua for an example.

pkey:derive

syntax: txt, err = pk:derive(peer_key)

Derive public key algorithm shared secret peer_key, which must be a pkey instance.

See examples/x25519-dh.lua for an example on how key exchange works for X25519 keys with DH algorithm.

pkey:tostring

syntax: txt, err = pk:tostring(private_or_public?, fmt?, is_pkcs1?)

Outputs private key or public key of pkey instance in PEM-formatted text. The first argument must be a choice of public, PublicKey, private, PrivateKey or nil.

The second argument fmt can be PEM, DER, JWK or nil. If both arguments are omitted, this functions returns the PEM representation of public key.

If is_pkcs1 is set to true, the output is encoded using a PKCS#1 RSAPublicKey structure; PKCS#1 encoding is currently supported for RSA key in PEM format. Writing out a PKCS#1 encoded RSA key is currently not supported when using with OpenSSL 3.0.

pkey:to_PEM

syntax: pem, err = pk:to_PEM(private_or_public?, is_pkcs1?)

Equivalent to pkey:tostring(private_or_public, "PEM", is_pkcs1).

resty.openssl.bn

Module to expose BIGNUM structure. Note bignum is a big integer, no float operations (like square root) are supported.

bn.new

syntax: b, err = bn.new(number?)

syntax: b, err = bn.new(string?, base?)

Creates a bn instance. The first argument can be:

• nil to creates an empty bn instance.
• A Lua number to initialize the bn instance.
• A string to initialize the bn instance. The second argument base specifies the base of the string, and can take value from (compatible with Ruby OpenSSL.BN API):
• 10 or omitted, for decimal string ("23333")
• 16, for hex encoded string ("5b25")
• 2, for binary string ("\x5b\x25")
• 0, for MPI formated string ("\x00\x00\x00\x02\x5b\x25")

MPI is a format that consists of the number's length in bytes represented as a 4-byte big-endian number, and the number itself in big-endian format, where the most significant bit signals a negative number (the representation of numbers with the MSB set is prefixed with null byte).

bn.dup

syntax: b, err = bn.dup(bn_ptr_cdata)

Duplicates a BIGNUM* to create a new bn instance.

bn.istype

syntax: ok = bn.istype(table)

Returns true if table is an instance of bn. Returns false otherwise.

bn.set

syntax: b, err = bn:set(number)

syntax: b, err = bn:set(string, base?)

Reuse the existing bn instance and reset its value with given number or string. Refer to bn.new for the type of arguments supported.

bn.from_binary, bn:to_binary

syntax: bn, err = bn.from_binary(bin)

syntax: bin, err = bn:to_binary(padto?)

Creates a bn instance from binary string.

Exports the BIGNUM value in binary string.

bn:to_binary accepts an optional number argument padto that can be used to pad leading zeros to the output to a specific length.

local to_hex = require "resty.string".to_hex
local b, err = require("resty.openssl.bn").from_binary("\x5b\x25")
local bin, err = b:to_binary()
ngx.say(to_hex(bin))
-- outputs "5b25

bn.from_mpi, bn:to_mpi

syntax: bn, err = bn.from_mpi(bin)

syntax: bin, err = bn:to_mpi()

Creates a bn instance from MPI formatted binary string.

Exports the BIGNUM value in MPI formatted binary string.

local to_hex = require "resty.string".to_hex
local b, err = require("resty.openssl.bn").from_mpi("\x00\x00\x00\x02\x5b\x25")
local bin, err = b:to_mpi()
ngx.say(to_hex(bin))
-- outputs "000000025b25

bn.from_hex, bn:to_hex

syntax: bn, err = bn.from_hex(hex)

syntax: hex, err = bn:to_hex()

Creates a bn instance from hex encoded string. Note that the leading 0x should not be included. A leading - indicating the sign may be included.

Exports the bn instance to hex encoded string.

local bn = require("resty.openssl.bn")
local b = bn.from_hex("5B25")
local hex, err = b:to_hex()
ngx.say(hex)
-- outputs "5B25"

bn.from_dec, bn:to_dec

syntax: bn, err = bn.from_dec(dec)

syntax: dec, err = bn:to_dec()

Creates a bn instance from decimal string. A leading - indicating the sign may be included.

Exports the bn instance to decimal string.

local bn = require("resty.openssl.bn")
local b = bn.from_dec("23333")
local dec, err = b:to_dec()
ngx.say(dec)
-- outputs "23333"

bn:to_number

syntax: n, err = bn:to_number()

syntax: n, err = bn:tonumber()

Export the lowest 32 bits or 64 bits part (based on the ABI) of bn instance to a number. This is useful when user wants to perform bitwise operations.

local bn = require("resty.openssl.bn")
local b = bn.from_dec("23333")
local n, err = b:to_number()
ngx.say(n)
-- outputs 23333
ngx.say(type(n))
-- outputs "number"

bn.generate_prime

syntax: bn, err = bn.generate_prime(bits, safe)

Generates a pseudo-random prime number of bit length bits.

If safe is true, it will be a safe prime (i.e. a prime p so that (p-1)/2 is also prime).

The PRNG must be seeded prior to calling BN_generate_prime_ex(). The prime number generation has a negligible error probability.

bn:__metamethods

Various mathematical operations can be performed as if it's a number.

local bn = require("resty.openssl.bn")
local a = bn.new(123456)
local b = bn.new(222)
 -- the following returns a bn
local r
r = -a
r = a + b
r = a - b
r = a * b
r = a / b -- equal to bn:idiv, returns floor division
r = a % b
-- all operations can be performed between number and bignum
r = a + 222
r = 222 + a
-- the following returns a bool
local bool
bool = a < b
bool = a >= b
-- compare between number will not work
-- WRONG: bool = a < 222

bn:add, bn:sub, bn:mul, bn:div, bn:exp, bn:mod, bn:gcd

syntax: r = a:op(b)

syntax: r = bn.op(a, b)

Perform mathematical operations op.

• add: add
• sub: subtract
• mul: multiply
• div, idiv: floor division (division with rounding down to nearest integer)
• exp, pow: the b-th power of a, this function is faster than repeated a * a * ....
• mod: modulo
• gcd: the greatest common divider of a and b.

Note that add, sub, mul, div, mod is also available with +, -, *, /, % operaters. See above section for examples.

local bn = require("resty.openssl.bn")
local a = bn.new(123456)
local b = bn.new(9876)
local r
-- the followings are equal
r = a:add(b)
r = bn.add(a, b)
r = a:add(9876)
r = bn.add(a, 9876)
r = bn.add(123456, b)
r = bn.add(123456, 9876)

bn:sqr

syntax: r = a:sqr()

syntax: r = bn.sqr(a)

Computes the 2-th power of a. This function is faster than r = a * a.

bn:mod_add, bn:mod_sub, bn:mod_mul, bn:mod_exp

syntax: r = a:op(b, m)

syntax: r = bn.op(a, b, m)

Perform modulo mathematical operations op.

• mod_add: adds a to b modulo m
• mod_sub: substracts b from a modulo m
• mod_mul: multiplies a by b and finds the non-negative remainder respective to modulus m
• mod_exp, mod_pow: computes a to the b-th power modulo m (r=a^b % m). This function uses less time and space than exp. Do not call this function when m is even and any of the parameters have the BN_FLG_CONSTTIME flag set.

local bn = require("resty.openssl.bn")
local a = bn.new(123456)
local b = bn.new(9876)
local r
-- the followings are equal
r = a:mod_add(b, 3)
r = bn.mod_add(a, b, 3)
r = a:mod_add(9876, 3)
r = bn.mod_add(a, 9876, 3)
r = bn.mod_add(123456, b, 3)
r = bn.mod_add(123456, 9876, 3)

bn:mod_sqr

syntax: r = a:mod_sqr(m)

syntax: r = bn.mod_sqr(a, m)

Takes the square of a modulo m.

bn:lshift, bn:rshift

syntax: r = bn:lshift(bit)

syntax: r = bn.lshift(a, bit)

syntax: r = bn:rshift(bit)

syntax: r = bn.rshift(a, bit)

Bit shift a to bit bits.

bn:is_zero, bn:is_one, bn:is_odd, bn:is_word

syntax: ok = bn:is_zero()

syntax: ok = bn:is_one()

syntax: ok = bn:is_odd()

syntax: ok, err = bn:is_word(n)

Checks if bn is 0, 1, and odd number or a number n respectively.

bn:is_prime

syntax: ok, err = bn:is_prime(nchecks?)

Checks if bn is a prime number. Returns true if it is prime with an error probability of less than 0.25^nchecks and error if any. If omitted, nchecks is set to 0 which means to select number of iterations basedon the size of the number

This function perform a Miller-Rabin probabilistic primality test with nchecks iterations. If nchecks == BN_prime_checks (0), a number of iterations is used that yields a false positive rate of at most 2^-64 for random input. The error rate depends on the size of the prime and goes down for bigger primes. The rate is 2^-80 starting at 308 bits, 2^-112 at 852 bits, 2^-128 at 1080 bits, 2^-192 at 3747 bits and 2^-256 at 6394 bits.

When the source of the prime is not random or not trusted, the number of checks needs to be much higher to reach the same level of assurance: It should equal half of the targeted security level in bits (rounded up to the next integer if necessary). For instance, to reach the 128 bit security level, nchecks should be set to 64.

See also BN_is_prime(3).

resty.openssl.cipher

Module to interact with symmetric cryptography (EVP_CIPHER).

cipher.new

syntax: d, err = cipher.new(cipher_name, properties?)

Creates a cipher instance. cipher_name is a case-insensitive string of cipher algorithm name. To view a list of cipher algorithms implemented, use openssl.list_cipher_algorithms or openssl list -cipher-algorithms

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

cipher.istype

syntax: ok = cipher.istype(table)

Returns true if table is an instance of cipher. Returns false otherwise.

cipher.set_buffer_size

syntax: ok = cipher.set_buffer_size(sz)

Resize the internal buffer size used by all cipher instance. The default buffer size is 1024 bytes.

If you are expecting to pass input text larger than 1024 bytes at one time to update(), encrypt() or decrypt(), setting the buffer to larger than the expected input size will improve performance by let more code to be JIT-able.

Avoid call this function at hotpath, as this re-allocate the buffer every time it's called.

cipher:get_provider_name

syntax: name = cipher:get_provider_name()

Returns the provider name of cipher.

This function is available since OpenSSL 3.0.

cipher:gettable_params, cipher:settable_params, cipher:get_param, cipher:set_params

Query settable or gettable params and set or get params. See Generic EVP parameter getter/setter.

cipher:encrypt

syntax: s, err = cipher:encrypt(key, iv?, s, no_padding?, aead_aad?)

Encrypt the text s with key key and IV iv. Returns the encrypted text in raw binary string and error if any. Optionally accepts a boolean no_padding which tells the cipher to enable or disable padding and default to false (enable padding). If no_padding is true, the length of s must then be a multiple of the block size or an error will occur.

When using GCM or CCM mode or chacha20-poly1305 cipher, it's also possible to pass the Additional Authenticated Data (AAD) as the fifth argument.

This function is a shorthand of cipher:init, cipher:set_aead_aad (if appliable) then cipher:final.

cipher:decrypt

syntax: s, err = cipher:decrypt(key, iv?, s, no_padding?, aead_aad?, aead_tag?)

Decrypt the text s with key key and IV iv. Returns the decrypted text in raw binary string and error if any. Optionally accepts a boolean no_padding which tells the cipher to enable or disable padding and default to false (enable padding). If no_padding is true, the length of s must then be a multiple of the block size or an error will occur; also, padding in the decrypted text will not be removed.

When using GCM or CCM mode or chacha20-poly1305 cipher, it's also possible to pas the Additional Authenticated Data (AAD) as the fifth argument and authentication tag as the sixth argument.

This function is a shorthand of cipher:init, cipher:set_aead_aad (if appliable), cipher:set_aead_tag (if appliable) then cipher:final.

cipher:init

syntax: ok, err = cipher:init(key, iv?, opts?)

Initialize the cipher with key key and IV iv. The optional third argument is a table consists of:

{
    is_encrypt = false,
    no_padding = false,
}

Calling function is needed before cipher:update and cipher:final if the cipher is not being initialized already. But not cipher:encrypt and cipher:decrypt.

If you wish to reuse cipher instance multiple times, calling this function is necessary to clear the internal state of the cipher. The shorthand functions cipher:encrypt and cipher:decrypt already take care of initialization and reset.

cipher:update

syntax: s, err = cipher:update(partial, ...)

Updates the cipher with one or more strings. If the cipher has larger than block size of data to flush, the function will return a non-empty string as first argument. This function can be used in a streaming fashion to encrypt or decrypt continous data stream.

cipher:update_aead_aad

syntax: ok, err = cipher:update_aead_aad(aad)

Provides AAD data to the cipher, this function can be called more than one times.

cipher:get_aead_tag

syntax: tag, err = cipher:get_aead_tag(size?)

Gets the authentication tag from cipher with length specified as size. If omitted, a tag with length of half of the block size will be returned. The size cannot exceed block size.

This function can only be called after encryption is finished.

cipher:set_aead_tag

syntax: ok, err = cipher:set_aead_tag(tag)

Set the authentication tag of cipher with tag.

This function can only be called before decryption starts.

cipher:final

syntax: s, err = cipher:final(partial?)

Returns the encrypted or decrypted text in raw binary string, optionally accept one string to encrypt or decrypt.

-- encryption
local c, err = require("resty.openssl.cipher").new("aes256")
c:init(string.rep("0", 32), string.rep("0", 16), {
    is_encrypt = true,
})
c:update("🦢")
local cipher, err = c:final()
ngx.say(ngx.encode_base64(cipher))
-- outputs "vGJRHufPYrbbnYYC0+BnwQ=="
-- OR:
local c, err = require("resty.openssl.cipher").new("aes256")
local cipher, err = c:encrypt(string.rep("0", 32), string.rep("0", 16), "🦢")
ngx.say(ngx.encode_base64(cipher))
-- outputs "vGJRHufPYrbbnYYC0+BnwQ=="

-- decryption
local encrypted = ngx.decode_base64("vGJRHufPYrbbnYYC0+BnwQ==")
local c, err = require("resty.openssl.cipher").new("aes256")
c:init(string.rep("0", 32), string.rep("0", 16), {
    is_encrypt = false,
})
c:update(encrypted)
local cipher, err = c:final()
ngx.say(cipher)
-- outputs "🦢"
-- OR:
local c, err = require("resty.openssl.cipher").new("aes256")
local cipher, err = c:decrypt(string.rep("0", 32), string.rep("0", 16), encrypted)
ngx.say(cipher)
-- outputs "🦢"

Note: in some implementations like libsodium or Java, AEAD ciphers append the tag (or MAC) at the end of encrypted ciphertext. In such case, user will need to manually cut off the tag with correct size(usually 16 bytes) and pass in the ciphertext and tag seperately.

See examples/aes-gcm-aead.lua for an example to use AEAD modes with authentication.

cipher:derive

syntax: key, iv, err = cipher:derive(key, salt?, count?, md?)

Derive a key and IV (if appliable) from given material that can be used in current cipher. This function is useful mainly to work with keys that were already derived from same algorithm. Newer applications should use a more modern algorithm such as PBKDF2 provided by kdf.derive.

count is the iteration count to perform. If it's omitted, it's set to 1. Note the recent version of openssl enc cli tool automatically use PBKDF2 if -iter is set to larger than 1, while this function will not. To use PBKDF2 to derive a key, please refer to kdf.derive.

md is the message digest name to use, it can take one of the values md2, md5, sha or sha1. If it's omitted, it's default to sha1.

local cipher = require("resty.openssl.cipher").new("aes-128-cfb")
local key, iv, err = cipher:derive("x")
-- equivalent to `openssl enc -aes-128-cfb -pass pass:x -nosalt -P -md sha1`

resty.openssl.digest

Module to interact with message digest (EVP_MD_CTX).

digest.new

syntax: d, err = digest.new(digest_name?, properties?)

Creates a digest instance. digest_name is a case-insensitive string of digest algorithm name. To view a list of digest algorithms implemented, use openssl.list_digest_algorithms or openssl list -digest-algorithms.

If digest_name is omitted, it's default to sha1. Specially, the digest_name "null" represents a "null" message digest that does nothing: i.e. the hash it returns is of zero length.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

digest.istype

syntax: ok = digest.istype(table)

Returns true if table is an instance of digest. Returns false otherwise.

digest:get_provider_name

syntax: name = digest:get_provider_name()

Returns the provider name of digest.

This function is available since OpenSSL 3.0.

digest:gettable_params, digest:settable_params, digest:get_param, digest:set_params

Query settable or gettable params and set or get params. See Generic EVP parameter getter/setter.

digest:update

syntax: ok, err = digest:update(partial, ...)

Updates the digest with one or more strings.

digest:final

syntax: str, err = digest:final(partial?)

Returns the digest in raw binary string, optionally accept one string to digest.

local d, err = require("resty.openssl.digest").new("sha256")
d:update("🦢")
local digest, err = d:final()
ngx.say(ngx.encode_base64(digest))
-- outputs "tWW/2P/uOa/yIV1gRJySJLsHq1xwg0E1RWCvEUDlla0="
-- OR:
local d, err = require("resty.openssl.digest").new("sha256")
local digest, err = d:final("🦢")
ngx.say(ngx.encode_base64(digest))
-- outputs "tWW/2P/uOa/yIV1gRJySJLsHq1xwg0E1RWCvEUDlla0="

digest:reset

syntax: ok, err = digest:reset()

Reset the internal state of digest instance as it's just created by digest.new. It calls EVP_DigestInit_ex under the hood.

User must call this before reusing the same digest instance.

resty.openssl.hmac

Module to interact with hash-based message authentication code (HMAC_CTX).

Use of this module is deprecated since OpenSSL 3.0, please use resty.openssl.mac instead.

hmac.new

syntax: h, err = hmac.new(key, digest_name?)

Creates a hmac instance. digest_name is a case-insensitive string of digest algorithm name. To view a list of digest algorithms implemented, use openssl.list_digest_algorithms or openssl list -digest-algorithms.

If digest_name is omitted, it's default to sha1.

hmac.istype

syntax: ok = hmac.istype(table)

Returns true if table is an instance of hmac. Returns false otherwise.

hmac:update

syntax: ok, err = hmac:update(partial, ...)

Updates the HMAC with one or more strings.

hmac:final

syntax: str, err = hmac:final(partial?)

Returns the HMAC in raw binary string, optionally accept one string to digest.

local d, err = require("resty.openssl.hmac").new("goose", "sha256")
d:update("🦢")
local hmac, err = d:final()
ngx.say(ngx.encode_base64(hmac))
-- outputs "k2UcrRp25tj1Spff89mJF3fAVQ0lodq/tJT53EYXp0c="
-- OR:
local d, err = require("resty.openssl.hmac").new("goose", "sha256")
local hmac, err = d:final("🦢")
ngx.say(ngx.encode_base64(hmac))
-- outputs "k2UcrRp25tj1Spff89mJF3fAVQ0lodq/tJT53EYXp0c="

hmac:reset

syntax: ok, err = hmac:reset()

Reset the internal state of hmac instance as it's just created by hmac.new. It calls HMAC_Init_ex under the hood.

User must call this before reusing the same hmac instance.

resty.openssl.mac

Module to interact with message authentication code (EVP_MAC).

mac.new

syntax: h, err = mac.new(key, mac, cipher?, digest?, properties?)

Creates a mac instance. mac is a case-insensitive string of MAC algorithm name. To view a list of digest algorithms implemented, use openssl.list_mac_algorithms or openssl list -mac-algorithms.

At least one of cipher or digest must be specified.

cipher is a case-insensitive string of digest algorithm name. To view a list of digest algorithms implemented, use openssl.list_cipher_algorithms or openssl list -cipher-algorithms. digest is a case-insensitive string of digest algorithm name. To view a list of digest algorithms implemented, use openssl.list_digest_algorithms or openssl list -digest-algorithms. properties parameter can be used to explictly select provider to fetch algorithms.

mac.istype

syntax: ok = mac.istype(table)

Returns true if table is an instance of mac. Returns false otherwise.

mac:get_provider_name

syntax: name = mac:get_provider_name()

Returns the provider name of mac.

This function is available since OpenSSL 3.0.

mac:gettable_params, mac:settable_params, mac:get_param, mac:set_params

Query settable or gettable params and set or get params. See Generic EVP parameter getter/setter.

mac:update

syntax: ok, err = mac:update(partial, ...)

Updates the MAC with one or more strings.

mac:final

syntax: str, err = mac:final(partial?)

Returns the MAC in raw binary string, optionally accept one string to digest.

local d, err = require("resty.openssl.mac").new("goose", "HMAC", nil, "sha256")
d:update("🦢")
local mac, err = d:final()
ngx.say(ngx.encode_base64(mac))
-- outputs "k2UcrRp25tj1Spff89mJF3fAVQ0lodq/tJT53EYXp0c="
-- OR:
local d, err = require("resty.openssl.mac").new("goose", "HMAC", nil, "sha256")
local hmac, err = d:final("🦢")
ngx.say(ngx.encode_base64(mac))
-- outputs "k2UcrRp25tj1Spff89mJF3fAVQ0lodq/tJT53EYXp0c="

mac:reset

syntax: ok, err = mac:reset()

Reset the internal state of mac instance as it's just created by mac.new. It calls EVP_MAC_Init under the hood.

User must call this before reusing the same mac instance.

resty.openssl.kdf

Module to interact with KDF (key derivation function).

kdf.derive (legacy)

syntax: key, err = kdf.derive(options)

Use of this module is deprecated since OpenSSL 3.0, please use kdf.new instead.

Derive a key from given material. Various KDFs are supported based on OpenSSL version:

PBKDF2(RFC 2898, NIST SP 800-132), HKDF(RFC 5869), TLS1-PRF(RFC 2246, RFC 5246 and NIST SP 800-135 r1) and scrypt(RFC 7914) is available.

options is a table that contains:

Key	Type	Description	Required or default
type	number	Type of KDF function to use, one of kdf.PBKDF2, kdf.SCRYPT, kdf.TLS1_PRF or kdf.HKDF	required
outlen	number	Desired key length to derive	required
pass	string	Initial key material to derive from	(empty string)
salt	string	Add some salt	(empty string)
md	string	Message digest method name to use, not effective for scrypt type	"sha1"
properties	string	Staring from OpenSSL 3.0, this function accepts an optional properties parameter
to explictly select provider to fetch algorithms.
pbkdf2_iter	number	PBKDF2 iteration count. RFC 2898 suggests an iteration count of at least 1000. Any value less than 1 is treated as a single iteration.	1
hkdf_key	string	HKDF key	required
hkdf_mode	number	HKDF mode to use, one of kdf.HKDEF_MODE_EXTRACT_AND_EXPAND, kdf.HKDEF_MODE_EXTRACT_ONLY or kdf.HKDEF_MODE_EXPAND_ONLY. To learn about mode, please refer to EVP_PKEY_CTX_set1_hkdf_key(3). Note with kdf.HKDEF_MODE_EXTRACT_ONLY, outlen is ignored and the output will be fixed size of HMAC-<md>.	kdf.HKDEF_MODE_EXTRACT_AND_EXPAND
hkdf_info	string	HKDF info value	(empty string)
tls1_prf_secret	string	TLS1-PRF secret	required
tls1_prf_seed	string	TLS1-PRF seed	required
scrypt_maxmem	number	Scrypt maximum memory usage in bytes	32 * 1024 * 1024
scrypt_N	number	Scrypt CPU/memory cost parameter, must be a power of 2	required
scrypt_r	number	Scrypt blocksize parameter (8 is commonly used)	required
scrypt_p	number	Scrypt parallelization parameter	required

local kdf = require("resty.openssl.kdf")
local key, err = kdf.derive({
    type = kdf.PBKDF2,
    outlen = 16,
    pass = "1234567",
    md = "md5",
    pbkdf2_iter = 1000,
})
ngx.say(ngx.encode_base64(key))
-- outputs "cDRFLQ7NWt+AP4i0TdBzog=="

key, err = kdf.derive({
    type = kdf.SCRYPT,
    outlen = 16,
    pass = "1234567",
    scrypt_N = 1024,
    scrypt_r = 8,
    scrypt_p = 16,
})
ngx.say(ngx.encode_base64(key))
-- outputs "9giFtxace5sESmRb8qxuOw=="

kdf.new

syntax: k, err = kdf.new(kdf_name?, properties?)

Creates a kdf instance. kdf_name is a case-insensitive string of kdf algorithm name. To view a list of kdf algorithms implemented, use openssl.list_kdf_algorithms or openssl list -kdf-algorithms.

This function is available since OpenSSL 3.0.

This function accepts an optional properties parameter to explictly select provider to fetch algorithms.

kdf.istype

syntax: ok = kdf.istype(table)

Returns true if table is an instance of kdf. Returns false otherwise.

This function is available since OpenSSL 3.0.

kdf:get_provider_name

syntax: name = kdf:get_provider_name()

Returns the provider name of kdf.

This function is available since OpenSSL 3.0.

kdf:gettable_params, kdf:settable_params, kdf:get_param, kdf:set_params

Query settable or gettable params and set or get params. See Generic EVP parameter getter/setter.

This function is available since OpenSSL 3.0.

kdf:derive

syntax: ok, err = kdf:derive(outlen, options?, options_count?)

Derive a key with length of outlen with options. Certain algorithms output fixed length of key where outlen should be unset.

options is a table map holding parameters passing to kdf. To view the list of parameters acceptable by selecter algorithm and provider, use kdf:settable_params.

Optionally, if length of options is known, user can provide its length through options_count to gain better performance where options table is relatively large.

local k = assert(kdf.new("PBKDF2"))
key = assert(k:derive(16, {
    pass = "1234567",
    iter = 1000,
    digest = "md5",
    salt = "",
}))
ngx.say(ngx.encode_base64(key))
-- outputs "cDRFLQ7NWt+AP4i0TdBzog=="
assert(k:reset())
-- kdf instance is reusable, user can set common parameters
-- through set_params and don't need to repeat in derive()
assert(k:set_params({
    iter = 1000,
    digest = "md5",
    salt = "",
}))
key = assert(k:derive(16, {
    pass = "1234567",
}))
ngx.say(ngx.encode_base64(key))
-- outputs "cDRFLQ7NWt+AP4i0TdBzog=="

local k = assert(kdf.new("HKDF"))
key = assert(k:derive(16, {
    digest = "md5",
    key = "secret",
    salt = "salt",
    info = "some info",
    mode = kdf.HKDEF_MODE_EXPAND_ONLY,
    -- as HKDF also accepts mode as string, use the literal below also works
    -- mode = "EXPAND_ONLY"
}))

This function is available since OpenSSL 3.0.

kdf:reset

syntax: ok, err = kdf:reset()

Reset the internal state of kdf instance as it's just created by kdf.new.

User must call this before reusing the same kdf instance.

resty.openssl.objects

Helpfer module on ASN1_OBJECT.

objects.obj2table

syntax: tbl = objects.bytes(asn1_obj)

Convert a ASN1_OBJECT pointer to a Lua table where

{
  id: OID of the object,
  nid: NID of the object,
  sn: short name of the object,
  ln: long name of the object,
}

objects.nid2table

syntax: tbl, err = objects.nid2table(nid)

Convert a NID to a Lua table, returns the same format as objects.obj2table

objects.txt2nid

syntax: nid, err = objects.txt2nid(txt)

Convert a text representation to NID.

resty.openssl.pkcs12

Module to interact with PKCS#12 format.

pkcs12.encode

syntax: der, err = pkcs12.encode(data, passphrase?, properties?)

Encode data in data to a PKCS#12 text.

data is a table that contains:

Key	Type	Description	Required or default
key	pkey	Private key	required
cert	x509	Certificate	required
cacerts	A list of x509 as Lua table	Additional certificates	[]
friendly_name	string	The name used for the supplied certificate and key	""
nid_key	number or string	The NID or text to specify algorithm to encrypt key	"PBE-SHA1-RC2-4" if compiled with RC2, otherwise "PBE-SHA1-3DES"; on OpenSSL 3.0 and later PBES2 with PBKDF2 and AES-256-CBC.
nid_cert	number or string	The NID or text to specify algorithm to encrypt cert	"PBE-SHA1-3DES"; on OpenSSL 3.0 and later PBES2 with PBKDF2 and AES-256-CBC
iter	number	Key iterration count	PKCS12_DEFAULT_ITER (2048)
mac_iter	number	MAC iterration count	1

passphrase is the string for encryption. If omitted, an empty string will be used.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

Note in OpenSSL 3.0 RC2 has been moved to legacy provider. In order to encode p12 data with RC2 encryption, you need to load the legacy provider first.

local pro = require "resty.openssl.provider"
local legacy_provider = assert(pro.load("legacy"))
local p12, err = pkcs12.encode({ key = key, cert = cert})
assert(legacy_provider:unload())

pkcs12.decode

syntax: data, err = pkcs12.decode(p12, passphrase?)

Decode a PKCS#12 text to Lua table data. Similar to the data table passed to pkcs12.encode, but onle cert, key, cacerts and friendly_name are returned.

passphrase is the string for encryption. If omitted, an empty string will be used.

Note in OpenSSL 3.0 RC2 has been moved to legacy provider. In order to decode p12 data with RC2 encryption, you need to load the legacy provider first.

resty.openssl.rand

Module to interact with random number generator.

rand.bytes

syntax: str, err = rand.bytes(length, private?, strength?)

Generate random bytes with length of length. If private is set to true, a private PRNG instance is used so that a compromise of the "public" PRNG instance will not affect the secrecy of these private values.

The bytes generated will have a security strength of at least strength bits.

resty.openssl.x509

Module to interact with X.509 certificates.

x509.new

syntax: crt, err = x509.new(txt?, fmt?, properties?)

Creates a x509 instance. txt can be PEM or DER formatted text; fmt is a choice of PEM, DER to load specific format, or * for auto detect.

When txt is omitted, new() creates an empty x509 instance.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

x509.dup

syntax: x509, err = x509.dup(x509_ptr_cdata)

Duplicates a X509* to create a new x509 instance.

x509.istype

syntax: ok = x509.istype(table)

Returns true if table is an instance of x509. Returns false otherwise.

x509:digest

syntax: d, err = x509:digest(digest_name?, properties?)

Returns a digest of the DER representation of the X509 certificate object in raw binary text.

digest_name is a case-insensitive string of digest algorithm name. To view a list of digest algorithms implemented, use openssl.list_digest_algorithms or openssl list -digest-algorithms.

If digest_name is omitted, it's default to sha1.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

x509:pubkey_digest

syntax: d, err = x509:pubkey_digest(digest_name?, properties?)

Returns a digest of the DER representation of the pubkey in the X509 object in raw binary text.

digest_name is a case-insensitive string of digest algorithm name. To view a list of digest algorithms implemented, use openssl.list_digest_algorithms or openssl list -digest-algorithms.

If digest_name is omitted, it's default to sha1.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

x509:check_private_key

syntax: match, err = x509:check_private_key(pkey)

Checks the consistency of private key pkey with the public key in current X509 object.

Returns a boolean indicating if it's a match and err describing the reason.

Note this function also checks if k itself is indeed a private key or not.

x509:get_*, x509:set_*

syntax: ok, err = x509:set_attribute(instance)

syntax: instance, err = x509:get_attribute()

Setters and getters for x509 attributes share the same syntax.

Attribute name	Type	Description
issuer_name	x509.name	Issuer of the certificate
not_before	number	Unix timestamp when certificate is not valid before
not_after	number	Unix timestamp when certificate is not valid after
pubkey	pkey	Public key of the certificate
serial_number	bn	Serial number of the certficate
subject_name	x509.name	Subject of the certificate
version	number	Version of the certificate, value is one less than version. For example, 2 represents version 3

Additionally, getters and setters for extensions are also available:

Extension name	Type	Description
subject_alt_name	x509.altname	Subject Alternative Name of the certificate, SANs are usually used to define "additional Common Names"
issuer_alt_name	x509.altname	Issuer Alternative Name of the certificate
basic_constraints	table,	Basic Constriants of the certificate
info_access	x509.extension.info_access	Authority Information Access of the certificate, contains information like OCSP reponder URL.
crl_distribution_points	x509.extension.dist_points	CRL Distribution Points of the certificate, contains information like Certificate Revocation List(CRL) URLs.

For all extensions, get_{extension}_critical and set_{extension}_critical is also supported to access the critical flag of the extension.

If the attribute is not found, getter will return nil, nil.

local x509, err = require("resty.openssl.x509").new()
err = x509:set_not_before(ngx.time())
local not_before, err = x509:get_not_before()
ngx.say(not_before)
-- outputs 1571875065

err = x509:set_basic_constraints_critical(true)

If type is a table, setter requires a table with case-insensitive keys to set; getter returns the value of the given case-insensitive key or a table of all keys if no key provided.

local x509, err = require("resty.openssl.x509").new()
err = x509:set_basic_constraints({
  cA = false,
  pathlen = 0,
})

ngx.say(x509:get_basic_constraints("pathlen"))
-- outputs 0

ngx.say(x509:get_basic_constraints())
-- outputs '{"ca":false,"pathlen":0}'

Note that user may also access the certain extension by x509:get_extension and x509:set_extension, while the later two function returns or requires extension instead. User may use getter and setters listed here if modification of current extensions is needed; use x509:get_extension or x509:set_extension if user are adding or replacing the whole extension or getters/setters are not implemented. If the getter returned a type of x509.* instance, it can be converted to a extension instance by extension:from_data, and thus used by x509:get_extension and x509:set_extension

x509:get_lifetime

syntax: not_before, not_after, err = x509:get_lifetime()

A shortcut of x509:get_not_before plus x509:get_not_after

x509:set_lifetime

syntax: ok, err = x509:set_lifetime(not_before, not_after)

A shortcut of x509:set_not_before plus x509:set_not_after.

x509:get_signature_name, x509:get_signature_nid, x509:get_signature_digest_name

syntax: sn, err = x509:get_signature_name()

syntax: nid, err = x509:get_signature_nid()

syntax: sn, err = x509:get_signature_digest_name()

Return the NID or the short name (SN) of the signature of the certificate.

x509:get_signature_digest_name returns the short name of the digest algorithm used to sign the certificate.

x509:get_extension

syntax: extension, pos, err = x509:get_extension(nid_or_txt, last_pos?)

Get X.509 extension matching the given NID to certificate, returns a resty.openssl.x509.extension instance and the found position.

If last_pos is defined, the function searchs from that position; otherwise it finds from beginning. Index is 1-based.

local ext, pos, err = x509:get_extension("keyUsage")
ngx.say(ext:text())
-- outputs "Digital Signature, Key Encipherment"

local ext, pos, err = x509:get_extension("subjectKeyIdentifier")
ngx.say(ext:text())
-- outputs "3D:42:13:57:8F:79:BE:30:7D:86:A9:AC:67:50:E5:56:3E:0E:AF:4F"

x509:add_extension

syntax: ok, err = x509:add_extension(extension)

Adds an X.509 extension to certificate, the first argument must be a resty.openssl.x509.extension instance.

local extension, err = require("resty.openssl.x509.extension").new(
  "keyUsage", "critical,keyCertSign,cRLSign"
)
local x509, err = require("resty.openssl.x509").new()
local ok, err = x509:add_extension(extension)

x509:set_extension

syntax: ok, err = x509:set_extension(extension, last_pos?)

Adds an X.509 extension to certificate, the first argument must be a resty.openssl.x509.extension instance. The difference from x509:add_extension is that in this function if a extension with same type already exists, the old extension will be replaced.

If last_pos is defined, the function replaces the same extension from that position; otherwise it finds from beginning. Index is 1-based. Returns nil, nil if not found.

Note this function is not thread-safe.

x509:get_extension_critical

syntax: ok, err = x509:get_extension_critical(nid_or_txt)

Get critical flag of the X.509 extension matching the given NID from certificate.

x509:set_extension_critical

syntax: ok, err = x509:set_extension_critical(nid_or_txt, crit?)

Set critical flag of the X.509 extension matching the given NID to certificate.

x509:get_ocsp_url

syntax: url_or_urls, err = x509:get_ocsp_url(return_all?)

Get OCSP URL(s) of the X.509 object. If return_all is set to true, returns a table containing all OCSP URLs; otherwise returns a string with first OCSP URL found. Returns nil if the extension is not found.

x509:get_crl_url

syntax: url_or_urls, err = x509:get_crl_url(return_all?)

Get CRL URL(s) of the X.509 object. If return_all is set to true, returns a table containing all CRL URLs; otherwise returns a string with first CRL URL found. Returns nil if the extension is not found.

x509:sign

syntax: ok, err = x509:sign(pkey, digest?)

Sign the certificate using the private key specified by pkey, which must be a resty.openssl.pkey that stores private key. Optionally accept digest parameter to set digest method, whichmust be a resty.openssl.digest instance. Returns a boolean indicating if signing is successful and error if any.

x509:verify

syntax: ok, err = x509:verify(pkey)

Verify the certificate signature using the public key specified by pkey, which must be a resty.openssl.pkey. Returns a boolean indicating if verification is successful and error if any.

x509:tostring

syntax: str, err = x509:tostring(fmt?)

Outputs certificate in PEM-formatted text or DER-formatted binary. The first argument can be a choice of PEM or DER; when omitted, this function outputs PEM by default.

x509:to_PEM

syntax: pem, err = x509:to_PEM()

Outputs the certificate in PEM-formatted text.

resty.openssl.x509.csr

Module to interact with certificate signing request (X509_REQ).

See examples/csr.lua for an example to generate CSR.

csr.new

syntax: csr, err = csr.new(txt?, fmt?, properties?)

Create an empty csr instance. txt can be PEM or DER formatted text; fmt is a choice of PEM, DER to load specific format, or * for auto detect.

When txt is omitted, new() creates an empty csr instance.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

csr.istype

syntax: ok = csr.istype(table)

Returns true if table is an instance of csr. Returns false otherwise.

csr:check_private_key

syntax: match, err = csr:check_private_key(pkey)

Checks the consistency of private key pkey with the public key in current CSR object.

Returns a boolean indicating if it's a match and err describing the reason.

Note this function also checks if k itself is indeed a private key or not.

csr:get_*, csr:set_*

syntax: ok, err = csr:set_attribute(instance)

syntax: instance, err = csr:get_attribute()

Setters and getters for x509 attributes share the same syntax.

Attribute name	Type	Description
pubkey	pkey	Public key of the certificate request
subject_name	x509.name	Subject of the certificate request
version	number	Version of the certificate request, value is one less than version. For example, 2 represents version 3

Additionally, getters and setters for extensions are also available:

Extension name	Type	Description
subject_alt_name	x509.altname	Subject Alternative Name of the certificate request, SANs are usually used to define "additional Common Names"

For all extensions, get_{extension}_critical and set_{extension}_critical is also supported to access the critical flag of the extension.

If the attribute is not found, getter will return nil, nil.

local csr, err = require("resty.openssl.csr").new()
err = csr:set_version(3)
local version, err = csr:get_version()
ngx.say(version)
-- outputs 3

Note that user may also access the certain extension by csr:get_extension and csr:set_extension, while the later two function returns or requires extension instead. User may use getter and setters listed here if modification of current extensions is needed; use csr:get_extension or csr:set_extension if user are adding or replacing the whole extension or getters/setters are not implemented. If the getter returned a type of x509.* instance, it can be converted to a extension instance by extension:from_data, and thus used by csr:get_extension and csr:set_extension

csr:set_subject_alt

Same as csr:set_subject_alt_name, this function is deprecated to align with naming convension with other functions.

csr:get_signature_name, csr:get_signature_nid, csr:get_signature_digest_name

syntax: sn, err = csr:get_signature_name()

syntax: nid, err = csr:get_signature_nid()

syntax: sn, err = csr:get_signature_digest_name()

Return the NID or the short name (SN) of the signature of the certificate request.

csr:get_signature_digest_name returns the short name of the digest algorithm used to sign the certificate.

csr:get_extension

syntax: extension, pos, err = csr:get_extension(nid_or_txt, pos?)

Get X.509 extension matching the given NID to certificate, returns a resty.openssl.x509.extension instance and the found position.

If last_pos is defined, the function searchs from that position; otherwise it finds from beginning. Index is 1-based.

local ext, pos, err = csr:get_extension("basicConstraints")

csr:get_extensions

syntax: extensions, err = csr:get_extensions()

Return all extensions as a resty.openssl.x509.extensions instance.

csr:add_extension

syntax: ok, err = csr:add_extension(extension)

Adds an X.509 extension to csr, the first argument must be a resty.openssl.x509.extension instance.

csr:set_extension

syntax: ok, err = csr:set_extension(extension)

Adds an X.509 extension to csr, the first argument must be a resty.openssl.x509.extension instance. The difference from csr:add_extension is that in this function if a extension with same type already exists, the old extension will be replaced.

Note this function is not thread-safe.

csr:get_extension_critical

syntax: ok, err = csr:get_extension_critical(nid_or_txt)

Get critical flag of the X.509 extension matching the given NID from csr.

csr:set_extension_critical

syntax: ok, err = csr:set_extension_critical(nid_or_txt, crit?)

Set critical flag of the X.509 extension matching the given NID to csr.

csr:sign

syntax: ok, err = csr:sign(pkey, digest?)

Sign the certificate request using the private key specified by pkey, which must be a resty.openssl.pkey that stores private key. Optionally accept digest parameter to set digest method, whichmust be a resty.openssl.digest instance. Returns a boolean indicating if signing is successful and error if any.

csr:verify

syntax: ok, err = csr:verify(pkey)

Verify the CSR signature using the public key specified by pkey, which must be a resty.openssl.pkey. Returns a boolean indicating if verification is successful and error if any.

csr:tostring

syntax: str, err = csr:tostring(fmt?)

Outputs certificate request in PEM-formatted text or DER-formatted binary. The first argument can be a choice of PEM or DER; when omitted, this function outputs PEM by default.

csr:to_PEM

syntax: pem, err = csr:to_PEM(?)

Outputs CSR in PEM-formatted text.

resty.openssl.x509.crl

Module to interact with X509_CRL(certificate revocation list).

crl.new

syntax: crt, err = crl.new(txt?, fmt?, properties?)

Creates a crl instance. txt can be PEM or DER formatted text; fmt is a choice of PEM, DER to load specific format, or * for auto detect.

When txt is omitted, new() creates an empty crl instance.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

crl.dup

syntax: crl, err = crl.dup(crl_ptr_cdata)

Duplicates a X509_CRL* to create a new crl instance.

crl.istype

syntax: ok = crl.istype(table)

Returns true if table is an instance of crl. Returns false otherwise.

crl:get_*, crl:set_*

syntax: ok, err = crl:set_attribute(instance)

syntax: instance, err = crl:get_attribute()

Setters and getters for crl attributes share the same syntax.

Attribute name	Type	Description
issuer_name	x509.name	Issuer of the CRL
last_update	number	Unix timestamp when CRL is not valid before
next_update	number	Unix timestamp when CRL is not valid after
version	number	Version of the certificate, value is one less than version. For example, 2 represents version 3

Additionally, getters and setters for extensions are also available:

Extension name	Type	Description

For all extensions, get_{extension}_critical and set_{extension}_critical is also supported to access the critical flag of the extension.

If the attribute is not found, getter will return nil, nil.

local crl, err = require("resty.openssl.crl").new()
err = crl:set_next_update(ngx.time())
local not_before, err = crl:get_next_update()
ngx.say(not_before)
-- outputs 1571875065

Note that user may also access the certain extension by crl:get_extension and crl:set_extension, while the later two function returns or requires extension instead. User may use getter and setters listed here if modification of current extensions is needed; use crl:get_extension or crl:set_extension if user are adding or replacing the whole extension or getters/setters are not implemented. If the getter returned a type of crl.* instance, it can be converted to a extension instance by extension:from_data, and thus used by crl:get_extension and crl:set_extension

crl:get_signature_name, crl:get_signature_nid, crl:get_signature_digest_name

syntax: sn, err = crl:get_signature_name()

syntax: nid, err = crl:get_signature_nid()

syntax: sn, err = crl:get_signature_digest_name()

Return the NID or the short name (SN) of the signature of the CRL.

crl:get_signature_digest_name returns the short name of the digest algorithm used to sign the certificate.

crl:get_by_serial

syntax: found_revoked, err = crl:get_by_serial(serial)

Find if given serial is in the CRL, serial can be bn instance, or a hexadecimal string. Returns a table if found where:

{
  serial_number: serial number of the revoked cert in hexadecimal string,
  revoked_date: revoked date of the cert as unix timestamp
}

Returns false if not found; specially if a serial number is removed from CRL, then false, "not revoked (removeFromCRL)" is returned.

crl:get_extension

syntax: extension, pos, err = crl:get_extension(nid_or_txt, last_pos?)

Get X.509 extension matching the given NID to CRL, returns a resty.openssl.x509.extension instance and the found position.

If last_pos is defined, the function searchs from that position; otherwise it finds from beginning. Index is 1-based.

crl:add_extension

syntax: ok, err = crl:add_extension(extension)

Adds an X.509 extension to CRL, the first argument must be a resty.openssl.x509.extension instance.

crl:set_extension

syntax: ok, err = crl:set_extension(extension, last_pos?)

Adds an X.509 extension to CRL, the first argument must be a resty.openssl.x509.extension instance. The difference from crl:add_extension is that in this function if a extension with same type already exists, the old extension will be replaced.

If last_pos is defined, the function replaces the same extension from that position; otherwise it finds from beginning. Index is 1-based. Returns nil, nil if not found.

Note this function is not thread-safe.

crl:get_extension_critical

syntax: ok, err = crl:get_extension_critical(nid_or_txt)

Get critical flag of the X.509 extension matching the given NID from CRL.

crl:set_extension_critical

syntax: ok, err = crl:set_extension_critical(nid_or_txt, crit?)

Set critical flag of the X.509 extension matching the given NID to CRL.

crl:add_revoked

syntax: ok, err = crl:add_revoked(revoked)

Adds a resty.openssl.x509.revoked instance to the CRL.

crl:sign

syntax: ok, err = crl:sign(pkey, digest?)

Sign the CRL using the private key specified by pkey, which must be a resty.openssl.pkey that stores private key. Optionally accept digest parameter to set digest method, whichmust be a resty.openssl.digest instance. Returns a boolean indicating if signing is successful and error if any.

crl:verify

syntax: ok, err = crl:verify(pkey)

Verify the CRL signature using the public key specified by pkey, which must be a resty.openssl.pkey. Returns a boolean indicating if verification is successful and error if any.

crl:tostring

syntax: str, err = crl:tostring(fmt?)

Outputs CRL in PEM-formatted text or DER-formatted binary. The first argument can be a choice of PEM or DER; when omitted, this function outputs PEM by default.

crl:text

syntax: str, err = crl:text()

Outputs CRL in a human-readable format.

crl:to_PEM

syntax: pem, err = crl:to_PEM()

Outputs the CRL in PEM-formatted text.

crl:__metamethods

syntax: for i, revoked in ipairs(crl)

syntax: len = #crl

syntax: revoked = crl[i]

Access the revoked list as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag; otherwise use all, each, index and count instead.

See also functions for stack-like objects.

Each returned object is a table where:

{
  serial_number: serial number of the revoked cert in hexadecimal string,
  revoked_date: revoked date of the cert as unix timestamp
}

local f = io.open("t/fixtures/TrustAsiaEVTLSProCAG2.crl"):read("*a")
local crl = assert(require("resty.openssl.x509.crl").new(f))

for _, obj in ipairs(crl) do
  ngx.say(require("cjson").encode(obj))
end
-- outputs '{"revocation_date":1577753344,"serial_number":"09159859CAC0C90203BB34C5A012C2A3"}'

resty.openssl.x509.name

Module to interact with X.509 names.

name.new

syntax: name, err = name.new()

Creates an empty name instance.

name.dup

syntax: name, err = name.dup(name_ptr_cdata)

Duplicates a X509_NAME* to create a new name instance.

name.istype

syntax: ok = name.istype(table)

Returns true if table is an instance of name. Returns false otherwise.

name:add

syntax: name, err = name:add(nid_text, txt)

Adds an ASN.1 object to name. First arguments in the text representation of NID. Second argument is the plain text value for the ASN.1 object.

Returns the name instance itself on success, or nil and an error on failure.

This function can be called multiple times in a chained fashion.

local name, err = require("resty.openssl.x509.name").new()
local _, err = name:add("CN", "example.com")

_, err = name
    :add("C", "US")
    :add("ST", "California")
    :add("L", "San Francisco")

name:find

syntax: obj, pos, err = name:find(nid_text, last_pos?)

Finds the ASN.1 object with the given text representation of NID from the postition of last_pos. By omitting the last_pos parameter, find finds from the beginning.

Returns the object in a table as same format as decribed here, the position of the found object and error if any. Index is 1-based. Returns nil, nil if not found.

local name, err = require("resty.openssl.x509.name").new()
local _, err = name:add("CN", "example.com")
                    :add("CN", "example2.com")

local obj, pos, err = name:find("CN")
ngx.say(obj.blob, " at ", pos)
-- outputs "example.com at 1"
local obj, pos, err = name:find("2.5.4.3", 1)
ngx.say(obj.blob, " at ", pos)
-- outputs "example2.com at 2"

name:tostring

syntax: txt = name:tostring()

Outputs name in a text representation.

local name, err = require("resty.openssl.x509.name").new()
local _, err = name:add("CN", "example.com")
                    :add("CN", "example2.com")

ngx.say(name:tostring())
-- outputs "CN=example.com/CN=example2.com"

name:__metamethods

syntax: for k, obj in pairs(name)

syntax: len = #name

syntax: k, v = name[i]

Access the underlying objects as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag; otherwise use all, each, index and count instead.

See also functions for stack-like objects.

Each returned object is a table where:

{
  id: OID of the object,
  nid: NID of the object,
  sn: short name of the object,
  ln: long name of the object,
  blob: value of the object,
}

local name, err = require("resty.openssl.x509.name").new()
local _, err = name:add("CN", "example.com")

for k, obj in pairs(name) do
  ngx.say(k, ":", require("cjson").encode(obj))
end
-- outputs 'CN: {"sn":"CN","id":"2.5.4.3","nid":13,"blob":"3.example.com","ln":"commonName"}'

resty.openssl.x509.altname

Module to interact with GENERAL_NAMES, an extension to X.509 names.

altname.new

syntax: altname, err = altname.new()

Creates an empty altname instance.

altname.dup

syntax: altname, err = altname.dup(altname_ptr_cdata)

Duplicates a STACK_OF(GENERAL_NAMES) to create a new altname instance. The function creates a new stack but won't duplicates elements in the stack.

altname.istype

syntax: altname = digest.istype(table)

Returns true if table is an instance of altname. Returns false otherwise.

altname:add

syntax: altname, err = altname:add(key, value)

Adds a name to altname stack, first argument is case-insensitive and can be one of

RFC822Name
RFC822
Email
UniformResourceIdentifier
URI
DNSName
DNS
IP
IPAddress

This function can be called multiple times in a chained fashion.

altname:tostring

syntax: txt = altname:tostring()

Outputs altname in a text representation.

local altname, err = require("resty.openssl.x509.altname").new()

_, err = altname
    :add("DNS", "2.example.com")
    :add("DnS", "3.example.com")

ngx.say(altname:tostring())
-- outputs "DNS=2.example.com/DNS=3.example.com"

altname:__metamethods

syntax: for k, obj in pairs(altname)

syntax: len = #altname

syntax: k, v = altname[i]

Access the underlying objects as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag; otherwise use all, each, index and count instead.

See also functions for stack-like objects.

Only the following types are decoded, other types are decoded as "TYPE:<unsupported>":

RFC822Name / Email
URI
DNS
DirName

resty.openssl.x509.extension

Module to interact with every X.509 extensions.

This module is particular useful to create extensions not supported by x509.* modules or custom extensions.

extension.new

syntax: ext, err = extension.new(name, value, data?)

Creates a new extension instance. name and value are strings in OpenSSL arbitrary extension format.

data can be a table, string or nil. Where data is a table, the following key will be looked up:

data = {
  issuer = resty.openssl.x509 instance,
  subject = resty.openssl.x509 instance,
  request = resty.openssl.x509.csr instance,
  crl = resty.openssl.x509.crl instance,
  issuer_pkey = resty.openssl.pkey instance, -- >= OpenSSL 3.0
}

From OpenSSL 3.0, issuer_pkey can be specified as a fallback source for generating the authority key identifier extension when issuer is same as subject.

When data is a string, it's the full nconf string. Using section lookup from value to data is also supported.

Example usages:

local extension = require("resty.openssl.x509.extension")
-- extendedKeyUsage=serverAuth,clientAuth
local ext, err = extension.new("extendedKeyUsage", "serverAuth,clientAuth")
-- crlDistributionPoints=URI:http://myhost.com/myca.crl
ext, err = extension.new("crlDistributionPoints", "URI:http://myhost.com/myca.crl")
-- with section lookup
ext, err = extension.new(
  "crlDistributionPoints", "crldp1_section",
  [[
  [crldp1_section]
  fullname=URI:http://myhost.com/myca.crl
  CRLissuer=dirName:issuer_sect
  reasons=keyCompromise, CACompromise

  [issuer_sect]
  C=UK
  O=Organisation
  CN=Some Name
  ]]
)
-- combine section lookup with other value
ext, err = extension.new(
"certificatePolicies", "ia5org,1.2.3.4,1.5.6.7.8,@polsect",
  [[
  [polsect]
  policyIdentifier = 1.3.5.8
  CPS.1="http://my.host.name/"
  CPS.2="http://my.your.name/"
  userNotice.1=@notice

  [notice]
  explicitText="Explicit Text Here"
  organization="Organisation Name"
  noticeNumbers=1,2,3,4
 ]]
))
-- subjectKeyIdentifier=hash
local x509, err = require("resty.openssl.x509").new()
ext, err =  extension.new("subjectKeyIdentifier", "hash", {
    subject = x509
})

See examples/tls-alpn-01.lua for an example to create extension with an unknown nid.

extension.dup

syntax: ext, err = extension.dup(extension_ptr_cdata)

Creates a new extension instance from X509_EXTENSION* pointer.

extension.from_der

syntax: ext, ok = extension.from_der(der, nid_or_txt, crit?)

Creates a new extension instance. der is the ASN.1 encoded string to be set for the extension.

nid_or_txt is a number or text representation of NID and crit is the critical flag of the extension.

See examples/tls-alpn-01.lua for an example to create extension with an unknown nid.

extension:to_der

syntax: der, ok = extension:to_der()

Returns the ASN.1 encoded (DER) value of the extension.

nid_or_txt is a number or text representation of NID. Note DER is a binary encoding format. Consider using extension:text for human readable or printable output.

extension.from_data

syntax: ext, ok = extension.from_data(table, nid_or_txt, crit?)

Creates a new extension instance. table can be instance of:

• x509.altname
• x509.extension.info_access
• x509.extension.dist_points

nid_or_txt is a number or text representation of NID and crit is the critical flag of the extension.

extension.to_data

syntax: ext, ok = extension:to_data(nid_or_txt)

Convert the extension to another wrapper instance. Currently supported following:

• x509.altname

nid_or_txt is a number or text representation of NID.

extension.istype

syntax: ok = extension.istype(table)

Returns true if table is an instance of extension. Returns false otherwise.

extension:get_extension_critical

syntax: crit, err = extension:get_extension_critical()

Returns true if extension is critical. Returns false otherwise.

extension:set_extension_critical

syntax: ok, err = extension:set_extension_critical(crit)

Set the critical flag of the extension.

extension:get_object

syntax: obj = extension:get_object()

Returns the name of extension as ASN.1 Object. User can further use helper functions in resty.openssl.objects to print human readable texts.

extension:text

syntax: txt, err = extension:text()

Returns the text representation of extension. This functions calls X509V3_EXT_print under the hood, and fallback to ASN1_STRING_print if the former failed. It thus has exact same output with that of openssl x509 -text.

local objects = require "resty.openssl.objects"
ngx.say(cjson.encode(objects.obj2table(extension:get_object())))
-- outputs '{"ln":"X509v3 Subject Key Identifier","nid":82,"sn":"subjectKeyIdentifier","id":"2.5.29.14"}'
ngx.say(extension:text())
-- outputs "C9:C2:53:61:66:9D:5F:AB:25:F4:26:CD:0F:38:9A:A8:49:EA:48:A9"

extension:tostring

syntax: txt, err = extension:tostring()

Same as extension:text.

resty.openssl.x509.extension.dist_points

Module to interact with CRL Distribution Points(DIST_POINT stack).

dist_points.new

syntax: dp, err = dist_points.new()

Creates a new dist_points instance.

dist_points.dup

syntax: dp, err = dist_points.dup(dist_points_ptr_cdata)

Duplicates a STACK_OF(DIST_POINT) to create a new dist_points instance. The function creates a new stack but won't duplicates elements in the stack.

dist_points.istype

syntax: ok = dist_points.istype(table)

Returns true if table is an instance of dist_points. Returns false otherwise.

dist_points:__metamethods

syntax: for i, obj in ipairs(dist_points)

syntax: len = #dist_points

syntax: obj = dist_points[i]

Access the underlying objects as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag; otherwise use all, each, index and count instead.

See also functions for stack-like objects.

Each object returned when iterrating dist_points instance is a x509.altname instance.

local x = x509.new(io.open("/path/to/a_cert_has_dist_points.crt"):read("*a"))

local cdp = x:get_crl_distribution_points()

local an = cdp[1]
ngx.say(an:tostring())
-- or any other function for resty.openssl.x509.altname

for _, an in ipairs(cdp) do
  ngx.say(an:tostring())
end

resty.openssl.x509.extension.info_access

Module to interact with Authority Information Access data (AUTHORITY_INFO_ACCESS, ACCESS_DESCRIPTION stack).

info_access.new

syntax: aia, err = info_access.new()

Creates a new info_access instance.

info_access.dup

syntax: aia, err = info_access.dup(info_access_ptr_cdata)

Duplicates a AUTHORITY_INFO_ACCESS to create a new info_access instance. The function creates a new stack but won't duplicates elements in the stack.

info_access.istype

syntax: ok = info_access.istype(table)

Returns true if table is an instance of info_access. Returns false otherwise.

info_access:add

syntax: ok, err = info_access:add(x509)

Add a x509 object to the info_access. The first argument must be a resty.openssl.x509 instance.

info_access:__metamethods

syntax: for i, obj in ipairs(info_access)

syntax: len = #info_access

syntax: obj = info_access[i]

Access the underlying objects as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag; otherwise use all, each, index and count instead.

See also functions for stack-like objects.

Each object returned when iterrating dist_points instance is a table of NID type and values.

local cjson = require("cjosn")
local x509 = require("resty.openssl.x509")
local crt = x509.new(io.open("/path/to/a_cert_has_info_access.crt"):read("*a"))

local aia = crt:get_info_access()

ngx.say(cjson.encode(aia[1]))
-- outputs '[178,"URI","http:\/\/ocsp.starfieldtech.com\/"]'

for _, a in ipairs(aia) do
  ngx.say(cjson.encode(a))
end

resty.openssl.x509.extensions

Module to interact with X.509 Extension stack.

extensions.new

syntax: ch, err = extensions.new()

Creates a new extensions instance.

extensions.dup

syntax: ch, err = extensions.dup(extensions_ptr_cdata)

Duplicates a STACK_OF(X509_EXTENSION) to create a new extensions instance. The function creates a new stack but won't duplicates elements in the stack.

extensions.istype

syntax: ok = extensions.istype(table)

Returns true if table is an instance of extensions. Returns false otherwise.

extensions:add

syntax: ok, err = extensions:add(x509)

Add a x509 object to the extensions. The first argument must be a resty.openssl.x509 instance.

extensions:__metamethods

syntax: for i, obj in ipairs(extensions)

syntax: len = #extensions

syntax: obj = extensions[i]

Access the underlying objects as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag; otherwise use all, each, index and count instead.

See also functions for stack-like objects.

resty.openssl.x509.chain

Module to interact with X.509 stack.

chain.new

syntax: ch, err = chain.new()

Creates a new chain instance.

chain.dup

syntax: ch, err = chain.dup(chain_ptr_cdata)

Duplicates a STACK_OF(X509) to create a new chain instance. The function creates a new stack and increases reference count for all elements by 1. But it won't duplicate the elements themselves.

chain.istype

syntax: ok = chain.istype(table)

Returns true if table is an instance of chain. Returns false otherwise.

chain:add

syntax: ok, err = chain:add(x509)

Add a x509 object to the chain. The first argument must be a resty.openssl.x509 instance.

chain:__metamethods

syntax: for i, obj in ipairs(chain)

syntax: len = #chain

syntax: obj = chain[i]

Access the underlying objects as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag; otherwise use all, each, index and count instead.

See also functions for stack-like objects.

resty.openssl.x509.store

Module to interact with X.509 certificate store (X509_STORE).

store.new

syntax: st, err = store.new(properties?)

Creates a new store instance.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

store.istype

syntax: ok = store.istype(table)

Returns true if table is an instance of store. Returns false otherwise.

store:use_default

syntax: ok, err = store:use_default(properties?)

Loads certificates into the X509_STORE from the hardcoded default paths.

Note that to load "default" CAs correctly, usually you need to install a CA certificates bundle. For example, the package in Debian/Ubuntu is called ca-certificates.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

store:add

syntax: ok, err = store:add(x509_or_crl, skip_set_crl_check_flags?)

Adds a X.509 or a CRL object into store. The argument must be a resty.openssl.x509 instance or a resty.openssl.x509.crl instance.

By default, adding a CRL object will automatically set the flag to store X509_V_FLAG_CRL_CHECK. Setting the second optional argument to true will skip settting the flags.

store:load_file

syntax: ok, err = store:load_file(path, properties?)

Loads a X.509 certificate on file system into store.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

store:load_directory

syntax: ok, err = store:load_directory(path, properties?)

Loads a directory of X.509 certificates on file system into store. The certificates in the directory must be in hashed form, as documented in X509_LOOKUP_hash_dir(3).

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

store:set_purpose

syntax: ok, err = store:set_purpose(purpose)

Set the X509_STORE to match Key Usage and Extendend Key Usage when verifying the cert. Possible values are:

    sslclient   SSL client
    sslserver   SSL server
    nssslserver Netscape SSL server
    smimesign   S/MIME signing
    smimeencrypt    S/MIME encryption
    crlsign     CRL signing
    any         Any Purpose
    ocsphelper  OCSP helper
    timestampsign   Time Stamp signing

Normally user should use verify_method parameter of store:verify unless the purpose is not included in the default verify methods.

store:set_depth

syntax: ok, err = store:set_depth(depth)

Set the verify depth.

store:set_flags

syntax: ok, err = store:set_flags(flag1, flag2, ...)

Set the verify flags, available via store.verify_flags table:

    X509_V_FLAG_CB_ISSUER_CHECK              = 0x0,   -- Deprecated
    X509_V_FLAG_USE_CHECK_TIME               = 0x2,
    X509_V_FLAG_CRL_CHECK                    = 0x4,
    X509_V_FLAG_CRL_CHECK_ALL                = 0x8,
    X509_V_FLAG_IGNORE_CRITICAL              = 0x10,
    X509_V_FLAG_X509_STRICT                  = 0x20,
    X509_V_FLAG_ALLOW_PROXY_CERTS            = 0x40,
    X509_V_FLAG_POLICY_CHECK                 = 0x80,
    X509_V_FLAG_EXPLICIT_POLICY              = 0x100,
    X509_V_FLAG_INHIBIT_ANY                  = 0x200,
    X509_V_FLAG_INHIBIT_MAP                  = 0x400,
    X509_V_FLAG_NOTIFY_POLICY                = 0x800,
    X509_V_FLAG_EXTENDED_CRL_SUPPORT         = 0x1000,
    X509_V_FLAG_USE_DELTAS                   = 0x2000,
    X509_V_FLAG_CHECK_SS_SIGNATURE           = 0x4000,
    X509_V_FLAG_TRUSTED_FIRST                = 0x8000,
    X509_V_FLAG_SUITEB_128_LOS_ONLY          = 0x10000,
    X509_V_FLAG_SUITEB_192_LOS               = 0x20000,
    X509_V_FLAG_SUITEB_128_LOS               = 0x30000,
    X509_V_FLAG_PARTIAL_CHAIN                = 0x80000,
    X509_V_FLAG_NO_ALT_CHAINS                = 0x100000,
    X509_V_FLAG_NO_CHECK_TIME                = 0x200000,

store:set_flags(store.verify_flags.X509_V_FLAG_PARTIAL_CHAIN)

store:set_flags(store.verify_flags.X509_V_FLAG_PARTIAL_CHAIN,
                store.verify_flags.X509_V_FLAG_NO_CHECK_TIME)

store:set_flags(store.verify_flags.X509_V_FLAG_PARTIAL_CHAIN +
                store.verify_flags.X509_V_FLAG_NO_CHECK_TIME)

See X509_VERIFY_PARAM_set_flags(3) for explanation of each flag.

store:verify

syntax: chain, err = store:verify(x509, chain?, return_chain?, properties?, verify_method?, verify_flags?)

Verifies a X.509 object with the store. The first argument must be resty.openssl.x509 instance. Optionally accept a validation chain as second argument, which must be a resty.openssl.x509.chain instance.

If verification succeed, and return_chain is set to true, returns the proof of validation as a resty.openssl.x509.chain; otherwise returns true only. If verification failed, returns nil and error explaining the reason.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

verify_method can be set to use predefined verify parameters such as "default", "pkcs7", "smime_sign", "ssl_client" and "ssl_server". This set corresponding purpose, trust and couple of other defaults but does not override the parameters set from store:set_purpose.

verify_flags paramter is the additional verify flags to be set. See store:set_flags for all available flags.

store:check_revocation

syntax: ok, err = store:check_revocation(verified_chain, properties?)

Only does the revocation check. The first argument verified_chain must be a resty.openssl.x509.chain instance which could be returned from store_ctx:verify or be built by yourself. Note the first cert needs to be the end entity certificate you want to check and the second cert needs to be its issuer.

Staring from OpenSSL 3.0, this function accepts an optional properties parameter to explictly select provider to fetch algorithms.

Returns true when the certificate isn't revoked, otherwise returns nil and error explaining the reason.

resty.openssl.x509.revoked

Module to interact with X509_REVOKED.

revoked.new

syntax: ch, err = revoked.new(serial_number, time, reason)

Creates a new revoked instance. serial_number can be either a resty.openssl.bn instance or a number. time and reason must be numbers.

revoked.istype

syntax: ok = revoked.istype(table)

Returns true if table is an instance of revoked. Returns false otherwise.

resty.openssl.ssl

Module to interact with SSL connection.

This module is currently considered experimental.

Note: to use this module in production, user is encouraged to compile lua-resty-openssl-aux-module.

ssl.from_request

syntax: sess, err = ssl.from_request()

Wraps the SSL* instance from current downstream request.

ssl.from_socket

syntax: sess, err = ssl.from_socket(sock)

Wraps the SSL* instance from a TCP cosocket, the cosocket must have already been called sslhandshake.

ssl:get_peer_certificate

syntax: x509, err = ssl:get_peer_certificate()

Return the peer certificate as a x509 instance. Depending on the type of ssl, peer certificate means the server certificate on client side, or the client certificate on server side.

This function should be called after SSL handshake.

ssl:get_peer_cert_chain

syntax: chain, err = ssl:get_peer_certificate()

Return the whole peer certificate chain as a x509.chain instance. Depending on the type of ssl, peer certificate means the server certificate on client side, or the client certificate on server side.

This function should be called after SSL handshake.

ssl:set_ciphersuites, ssl:set_cipher_list

syntax: ok, err = ssl:set_ciphersuites(cipher_suite) syntax: ok, err = ssl:set_cipher_list(cipher_list)

Set the cipher suites string used in handshake. Use ssl:set_ciphersuites for TLSv1.3 andssl:set_cipher_list` for lower.

This function should be called before SSL handshake; for server this means this function is only effective in ssl_certificate_by or ssl_client_hello_by phases.

ssl:get_ciphers

syntax: ciphers, err = ssl:get_ciphers()

Get the cipher list string used in handshake as a string.

ssl:get_cipher_name

syntax: cipher_name, err = ssl:get_cipher_name()

Get the negotiated cipher name as a string.

This function should be called after SSL handshake.

ssl:set_timeout

syntax: ok, err = ssl:set_timeout(tm)

Set the timeout value for current session in seconds tm.

ssl:get_timeout

syntax: tm, err = ssl:set_timeout(tm)

Get the timeout value for current session in seconds.

ssl:set_verify

syntax: ok, err = ssl:set_verify(mode)

Set the verify mode in current session. Available modes are:

  ssl.SSL_VERIFY_NONE                 = 0x00,
  ssl.SSL_VERIFY_PEER                 = 0x01,
  ssl.SSL_VERIFY_FAIL_IF_NO_PEER_CERT = 0x02,
  ssl.SSL_VERIFY_CLIENT_ONCE          = 0x04,
  ssl.SSL_VERIFY_POST_HANDSHAKE       = 0x08,

This function should be called before SSL handshake; for server this means this function is only effective in ssl_certificate_by or ssl_client_hello_by phases.

ssl:add_client_ca

syntax: ok, err = ssl:add_client_ca(x509)

Add the CA name extracted from x509 to the list of CAs sent to the client when requesting a client certificate. x509 is a x509 instance. This function doesn't affect the verification result of client certificate.

This function should be called before SSL handshake; for server this means this function is only effective in ssl_certificate_by or ssl_client_hello_by phases.

ssl:set_options

syntax: bitmask, err = ssl:set_options(option, ...)

Set one or more options in current session. Available options are:

SSL options

  ssl.SSL_OP_NO_EXTENDED_MASTER_SECRET                = 0x00000001,
  ssl.SSL_OP_CLEANSE_PLAINTEXT                        = 0x00000002,
  ssl.SSL_OP_LEGACY_SERVER_CONNECT                    = 0x00000004,
  ssl.SSL_OP_TLSEXT_PADDING                           = 0x00000010,
  ssl.SSL_OP_SAFARI_ECDHE_ECDSA_BUG                   = 0x00000040,
  ssl.SSL_OP_IGNORE_UNEXPECTED_EOF                    = 0x00000080,
  ssl.SSL_OP_DISABLE_TLSEXT_CA_NAMES                  = 0x00000200,
  ssl.SSL_OP_ALLOW_NO_DHE_KEX                         = 0x00000400,
  ssl.SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS              = 0x00000800,
  ssl.SSL_OP_NO_QUERY_MTU                             = 0x00001000,
  ssl.SSL_OP_COOKIE_EXCHANGE                          = 0x00002000,
  ssl.SSL_OP_NO_TICKET                                = 0x00004000,
  ssl.SSL_OP_CISCO_ANYCONNECT                         = 0x00008000,
  ssl.SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION   = 0x00010000,
  ssl.SSL_OP_NO_COMPRESSION                           = 0x00020000,
  ssl.SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION        = 0x00040000,
  ssl.SSL_OP_NO_ENCRYPT_THEN_MAC                      = 0x00080000,
  ssl.SSL_OP_ENABLE_MIDDLEBOX_COMPAT                  = 0x00100000,
  ssl.SSL_OP_PRIORITIZE_CHACHA                        = 0x00200000,
  ssl.SSL_OP_CIPHER_SERVER_PREFERENCE                 = 0x00400000,
  ssl.SSL_OP_TLS_ROLLBACK_BUG                         = 0x00800000,
  ssl.SSL_OP_NO_ANTI_REPLAY                           = 0x01000000,
  ssl.SSL_OP_NO_SSLv3                                 = 0x02000000,
  ssl.SSL_OP_NO_TLSv1                                 = 0x04000000,
  ssl.SSL_OP_NO_TLSv1_2                               = 0x08000000,
  ssl.SSL_OP_NO_TLSv1_1                               = 0x10000000,
  ssl.SSL_OP_NO_TLSv1_3                               = 0x20000000,
  ssl.SSL_OP_NO_DTLSv1                                = 0x04000000,
  ssl.SSL_OP_NO_DTLSv1_2                              = 0x08000000,
  ssl.SSL_OP_NO_RENEGOTIATION                         = 0x40000000,
  ssl.SSL_OP_CRYPTOPRO_TLSEXT_BUG                     = 0x80000000,

Multiple options can be passed in seperatedly, or in a bitwise or bitmask.

assert(ssl:set_options(bit.bor(ssl.SSL_OP_NO_TLSv1_1, ssl.SSL_OP_NO_TLSv1_2)))
-- same as
assert(ssl:set_options(ssl.SSL_OP_NO_TLSv1_1, ssl.SSL_OP_NO_TLSv1_2))

Returns the options of current session in bitmask.

This function should be called before SSL handshake; for server this means this function is only effective in ssl_client_hello_by phase.

ssl:get_options

syntax: bitmask, err = ssl:get_options(readable?)

Get the options for current session. If readable is not set or set to false, the function return the bit mask for all optinos; if readable is set to true, the function returns a sorted Lua table containing literals for all options.

ssl:clear_options

syntax: bitmask, err = ssl:clear_options(option, ...)

Clear one or more options in current session. Available options are same as that in ssl:set_options.

Multiple options can be passed in seperatedly, or in a bitwise or bitmask.

assert(ssl:clear_options(bit.bor(ssl.SSL_OP_NO_TLSv1_1, ssl.SSL_OP_NO_TLSv1_2)))
-- same as
assert(ssl:clear_options(ssl.SSL_OP_NO_TLSv1_1, ssl.SSL_OP_NO_TLSv1_2))

Returns the options of current session in bitmask.

This function should be called before SSL handshake; for server this means this function is only effective in ssl_client_hello_by phase.

ssl:set_protocols

syntax: bitmask, err = ssl:set_protocols(protocol, ...)

Set avaialable protocols for handshake, this is a convenient function that calls ssl:set_options and ssl:clear_options to set appropriate options.

Returns the options of current session in bitmask.

This function should be called before SSL handshake; for server this means this function is only effective in ssl_client_hello_by phase.

assert(ssl:set_protocols("TLSv1.1", "TLSv1.2"))
-- same as
assert(ssl:set_options(ssl.SSL_OP_NO_SSL_MASK))
assert(ssl:clear_options(ssl.SSL_OP_NO_TLSv1_1, ssl.SSL_OP_NO_TLSv1_2))

resty.openssl.ssl_ctx

Module to interact with SSL_CTX context.

This module is currently considered experimental.

Note: to use this module in production, user is encouraged to compile lua-resty-openssl-aux-module.

ssl_ctx.from_request

syntax: ctx, err = ssl_ctx.from_request()

Wraps the SSL_CTX* instance from current downstream request.

ssl_ctx.from_socket

syntax: sess, err = ssl_ctx.from_socket(sock)

Wraps the SSL_CTX* instance from a TCP cosocket, the cosocket must have already been called sslhandshake.

ssl_ctx:set_alpns

syntax: ok, err = ssl_ctx:set_alpns(alpn, ...)

Set the ALPN list to be negotiated with peer. Each alpn is the plaintext literal for the protocol, like "h2".

Functions for stack-like objects

metamethods

syntax: for k, obj in pairs(x)

syntax: for k, obj in ipairs(x)

syntax: len = #x

syntax: obj = x[i]

Access the underlying objects as it's a Lua table. Make sure your LuaJIT compiled with -DLUAJIT_ENABLE_LUA52COMPAT flag.

Each object may only support either pairs or ipairs. Index is 1-based.

local name, err = require("resty.openssl.x509.name").new()
local _, err = name:add("CN", "example.com")

for k, obj in pairs(name) do
  ngx.say(k, ":", require("cjson").encode(obj))
end
-- outputs 'CN: {"sn":"CN","id":"2.5.4.3","nid":13,"blob":"3.example.com","ln":"commonName"}'

each

syntax: iter = x:each()

Return an iterator to traverse objects. Use this while LUAJIT_ENABLE_LUA52COMPAT is not enabled.

local name, err = require("resty.openssl.x509.name").new()
local _, err = name:add("CN", "example.com")

local iter = name:each()
while true do
  local k, obj = iter()
  if not k then
    break
  end
end

all

syntax: objs, err = x:all()

Returns all objects in the table. Use this while LUAJIT_ENABLE_LUA52COMPAT is not enabled.

count

syntax: len = x:count()

Returns count of objects of the table. Use this while LUAJIT_ENABLE_LUA52COMPAT is not enabled.

index

syntax: obj = x:index(i)

Returns objects at index of i of the table, index is 1-based. If index is out of bound, nil is returned.

General rules on garbage collection

• When a type is added or returned to another type, it's internal cdata is always copied.

  local name = require("resty.openssl.x509.name"):add("CN", "example.com")
  local x509 = require("resty.openssl.x509").new()
  -- `name` is copied when added to x509
  x509:set_subject_name(name)
  
  name:add("L", "Mars")
  -- subject_name in x509 will not be modified
  

• The creator set the GC handler; the user must not free it.
• For a stack:
• If it's created by new(): set GC handler to sk_TYPE_pop_free
  • The gc handler for elements being added to stack should not be set. Instead, rely on the gc handler of the stack to free each individual elements.
• If it's created by dup() (shallow copy):
  • If elements support reference counter (like X509): increase ref count for all elements by 1; set GC handler to sk_TYPE_pop_free.
  • If not, set GC handler to sk_free
  • Additionally, the stack duplicates the element when it's added to stack, a GC handler for the duplicate must be set. But a reference should be kept in Lua land to prevent premature gc of individual elements. (See x509.altname).
  • Shallow copy for stack is fine because in current design user can't modify the element in the stack directly. Each elemente is duplicated when added to stack and when returned.

Generic EVP parameter getter/setter

Starting from OpenSSL 3.0, this library provides a genric interface to get and set abitrary parameters from underlying implementation. This works for cipher, pkey, digest, mac and kdf.

Some can be used to provide equal results with existing functions, for example the following code produces same result.

local pkey = require("resty.openssl.pkey").new({ type = "EC" })
pkey:get_param("priv", nil, "bn") == pkey:get_parameters().private

local cipher = require("resty.openssl.cipher").new("aes-256-gcm")
cipher:encrypt(string.rep("0", 32), string.rep("0", "12"), "secret", false, "aad")
cipher:get_param("tag", 16) == cipher:get_aead_tag()

gettable_params

syntax: schema, err = x:gettable_params(raw?)

Returns the readable schema as a Lua table for all gettable params. When raw is set to true, the function returns the raw schema instead.

settable_params

syntax: schema, err = x:settable_params(raw?)

Returns the readable schema as a Lua table for all settable params. When raw is set to true, the function returns the raw schema instead.

local c = require("resty.openssl.cipher").new("aes-256-gcm")
print(cjson.encode(c:settable_params()))
-- outputs [["ivlen","unsigned integer (max 8 bytes large)"],["tag","octet string (arbitrary size)"],["tlsaad","octet string (arbitrary size)"],["tlsivfixed","octet string (arbitrary size)"],["tlsivinv","octet string (arbitrary size)"]]
print(cjson.encode(c:gettable_params()))
-- outputs [["keylen","unsigned integer (max 8 bytes large)"],["ivlen","unsigned integer (max 8 bytes large)"],["taglen","unsigned integer (max 8 bytes large)"],["iv","octet string (arbitrary size)"],["updated-iv","octet string (arbitrary size)"],["tag","octet string (arbitrary size)"],["tlsaadpad","unsigned integer (max 8 bytes large)"],["tlsivgen","octet string (arbitrary size)"]]

get_param

syntax: value, err = x:get_param(key, want_size?, want_type?)

Read the param key and return its value. The return value is a Lua number or a string. Certain params requires exact size to be set, in such case, want_size should be specified; if want_size is not specified and, the library use a buffer of 100 bytes to hold the return value. Certain params returns a special type, user should explictly set want_type as a string to correctly decode them. Currently want_type can only be "bn" or unset. Note it may also be necessary to increase temporary buffer size want_size when want_type is "bn".

local c = require("resty.openssl.cipher").new("aes-256-gcm")
print(c:get_param("taglen"))
-- outputs 16
print(c:get_param("tag"))
-- returns error, tag must have a explict size
print(c:get_param("tag", 16))
-- outputs the tag
local p = require("resty.openssl.pkey").new())
print(p:get_param("d"):to_hex())
-- returns error, d (private exponent) is a BIGNUM
print(p:get_param("d", 256, "bn"):to_hex())
-- returns d as resty.openssl.bn instance

set_params

syntax: ok, err = x:set_params(params)

Set params passed in with Lua table params. The library does limited type check, user is responsible for validity of input.

local k = require("resty.openssl.kdf").new("HKDF")
k:set_params({
    digest = "md5",
    salt = "salt",
    info = "some info",
    mode = kdf.HKDEF_MODE_EXPAND_ONLY,
    -- as HKDF also accepts mode as string, use the literal below also works
    -- mode = "EXPAND_ONLY"
}))

Code generation

Lots of functions and tests for X509, CSR and CRL are generated from templates under scripts directory. Those functions and tests are either commented with AUTO GENERATED or AUTOGEN.

When making changes to them, please update the template under scripts/templates instead. Then regenerate them again.

cd scripts
pip3 install -r requirements.txt
python3 ./x509_autogen.py

See Also

• luaossl
• API/ABI changes review for OpenSSL
• OpenSSL API manual

GitHub

You may find additional configuration tips and documentation for this module in the GitHub repository for nginx-module-openssl.