module JWT::Algos::Ecdsa

Constants

NAMED_CURVES
SUPPORTED

Public Instance Methods

asn1_to_raw(signature, public_key) click to toggle source
# File lib/jwt/algos/ecdsa.rb, line 70
def asn1_to_raw(signature, public_key)
  byte_size = (public_key.group.degree + 7) / 8
  OpenSSL::ASN1.decode(signature).value.map { |value| value.value.to_s(2).rjust(byte_size, "\x00") }.join
end
curve_by_name(name) click to toggle source
# File lib/jwt/algos/ecdsa.rb, line 57
def curve_by_name(name)
  NAMED_CURVES.fetch(name) do
    raise UnsupportedEcdsaCurve, "The ECDSA curve '#{name}' is not supported"
  end
end
raw_to_asn1(signature, private_key) click to toggle source
# File lib/jwt/algos/ecdsa.rb, line 63
def raw_to_asn1(signature, private_key)
  byte_size = (private_key.group.degree + 7) / 8
  sig_bytes = signature[0..(byte_size - 1)]
  sig_char = signature[byte_size..-1] || ''
  OpenSSL::ASN1::Sequence.new([sig_bytes, sig_char].map { |int| OpenSSL::ASN1::Integer.new(OpenSSL::BN.new(int, 2)) }).to_der
end
sign(algorithm, msg, key) click to toggle source
# File lib/jwt/algos/ecdsa.rb, line 33
def sign(algorithm, msg, key)
  curve_definition = curve_by_name(key.group.curve_name)
  key_algorithm = curve_definition[:algorithm]
  if algorithm != key_algorithm
    raise IncorrectAlgorithm, "payload algorithm is #{algorithm} but #{key_algorithm} signing key was provided"
  end

  digest = OpenSSL::Digest.new(curve_definition[:digest])
  asn1_to_raw(key.dsa_sign_asn1(digest.digest(msg)), key)
end
verify(algorithm, public_key, signing_input, signature) click to toggle source
# File lib/jwt/algos/ecdsa.rb, line 44
def verify(algorithm, public_key, signing_input, signature)
  curve_definition = curve_by_name(public_key.group.curve_name)
  key_algorithm = curve_definition[:algorithm]
  if algorithm != key_algorithm
    raise IncorrectAlgorithm, "payload algorithm is #{algorithm} but #{key_algorithm} verification key was provided"
  end

  digest = OpenSSL::Digest.new(curve_definition[:digest])
  public_key.dsa_verify_asn1(digest.digest(signing_input), raw_to_asn1(signature, public_key))
rescue OpenSSL::PKey::PKeyError
  raise JWT::VerificationError, 'Signature verification raised'
end