Module: JOSE::JWA

Extended by:
JWA
Included in:
JWA
Defined in:
lib/jose/jwa.rb

Overview

JWA stands for JSON Web Algorithms which is defined in RFC 7518.

Cryptographic Algorithm Fallback

Native implementations of all cryptographic and public key algorithms required by the JWA specifications are not present in current versions of Ruby.

JOSE will detect whether a specific algorithm is natively supported or not and, by default, it will mark the algorithm as unsupported if a native implementation is not found.

However, JOSE also has pure Ruby versions of many of the missing algorithms which can be used as a fallback by calling JOSE.crypto_fallback= and passing true.

Defined Under Namespace

Modules: AES_KW, ConcatKDF, Curve25519, Curve25519_RbNaCl, Curve25519_Ruby, Curve25519_Unsupported, Curve448, Curve448_Ruby, Curve448_Unsupported, Ed25519, Ed25519_RbNaCl, Ed448, PKCS1, PKCS7, SHA3, X25519, X25519_RbNaCl, X448 Classes: Edwards25519Point, Edwards448Point, EdwardsPoint, FieldElement

Constant Summary collapse

UCHAR_PACK =
'C*'.freeze
ZERO_PAD =
[0].pack('C').force_encoding('BINARY').freeze

Instance Method Summary collapse

Instance Method Details

#constant_time_compare(a, b) ⇒ Boolean

Performs a constant time comparison between two binaries to help avoid timing attacks.

Parameters:

  • a (String)
  • b (String)

Returns:

  • (Boolean)

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# File 'lib/jose/jwa.rb', line 28

def constant_time_compare(a, b)
  return false if a.empty? || b.empty? || a.bytesize != b.bytesize
  l = a.unpack "C#{a.bytesize}"

  res = 0
  b.each_byte { |byte| res |= byte ^ l.shift }
  return res == 0
end

#supportsHash

Returns the current listing of supported JOSE algorithms.

JOSE::JWA.supports
# => {:jwe=>
#   {:alg=>
#     ["A128GCMKW",
#      "A192GCMKW",
#      "A256GCMKW",
#      "A128KW",
#      "A192KW",
#      "A256KW",
#      "ECDH-ES",
#      "ECDH-ES+A128KW",
#      "ECDH-ES+A192KW",
#      "ECDH-ES+A256KW",
#      "PBES2-HS256+A128KW",
#      "PBES2-HS384+A192KW",
#      "PBES2-HS512+A256KW",
#      "RSA1_5",
#      "RSA-OAEP",
#      "RSA-OAEP-256",
#      "dir"],
#    :enc=>
#     ["A128GCM",
#      "A192GCM",
#      "A256GCM",
#      "A128CBC-HS256",
#      "A192CBC-HS384",
#      "A256CBC-HS512"],
#    :zip=>
#     ["DEF"]},
#  :jwk=>
#   {:kty=>
#     ["EC",
#      "OKP",
#      "RSA",
#      "oct"],
#    :kty_EC_crv=>
#     ["P-256",
#      "P-384",
#      "P-521"],
#    :kty_OKP_crv=>
#     ["Ed25519",
#      "Ed25519ph",
#      "Ed448",
#      "Ed448ph",
#      "X25519",
#      "X448"]},
#  :jws=>
#   {:alg=>
#     ["Ed25519",
#      "Ed25519ph",
#      "Ed448",
#      "Ed448ph",
#      "ES256",
#      "ES384",
#      "ES512",
#      "HS256",
#      "HS384",
#      "HS512",
#      "PS256",
#      "PS384",
#      "PS512",
#      "RS256",
#      "RS384",
#      "RS512",
#      "none"]}}

Returns:

  • (Hash)

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# File 'lib/jose/jwa.rb', line 122

def supports
  jwe_enc = __jwe_enc_support_check__([
    'A128GCM',
    'A192GCM',
    'A256GCM',
    'A128CBC-HS256',
    'A192CBC-HS384',
    'A256CBC-HS512'
  ])
  jwe_alg = __jwe_alg_support_check__([
    ['A128GCMKW', :block],
    ['A192GCMKW', :block],
    ['A256GCMKW', :block],
    ['A128KW', :block],
    ['A192KW', :block],
    ['A256KW', :block],
    ['ECDH-ES', :box],
    ['ECDH-ES+A128KW', :box],
    ['ECDH-ES+A192KW', :box],
    ['ECDH-ES+A256KW', :box],
    ['PBES2-HS256+A128KW', :block],
    ['PBES2-HS384+A192KW', :block],
    ['PBES2-HS512+A256KW', :block],
    ['RSA1_5', :rsa],
    ['RSA-OAEP', :rsa],
    ['RSA-OAEP-256', :rsa],
    ['dir', :direct]
  ], jwe_enc)
  jwe_zip = __jwe_zip_support_check__([
    'DEF'
  ], jwe_enc)
  jwk_kty, jwk_kty_EC_crv, jwk_kty_OKP_crv = __jwk_kty_support_check__([
    ['EC', ['P-256', 'P-384', 'P-521']],
    ['OKP', ['Ed25519', 'Ed25519ph', 'Ed448', 'Ed448ph', 'X25519', 'X448']],
    'RSA',
    'oct'
  ])
  jws_alg = __jws_alg_support_check__([
    'Ed25519',
    'Ed25519ph',
    'Ed448',
    'Ed448ph',
    'ES256',
    'ES384',
    'ES512',
    'HS256',
    'HS384',
    'HS512',
    'PS256',
    'PS384',
    'PS512',
    'RS256',
    'RS384',
    'RS512',
    'X25519',
    'X448',
    'none'
  ])
  return {
    jwe: {
      alg: jwe_alg,
      enc: jwe_enc,
      zip: jwe_zip
    },
    jwk: {
      kty: jwk_kty,
      kty_EC_crv: jwk_kty_EC_crv,
      kty_OKP_crv: jwk_kty_OKP_crv
    },
    jws: {
      alg: jws_alg
    }
  }
end