module Ed25519

The Ed25519 digital signatre algorithm rubocop:disable Metrics/LineLength

Constants

KEY_SIZE: Size of an Ed25519 key (public or private) in bytes
SIGNATURE_SIZE: Size of an Ed25519 signature in bytes
SelfTestFailure: Raised when the built-in self-test fails
VERSION
VerifyError: Raised when a signature fails to verify

Attributes

provider[RW]

Obtain the backend provider module used to perform signatures

Public Instance Methods

self_test() click to toggle source

Perform a self-test to ensure the selected provider is working

# File lib/ed25519.rb, line 46
def self_test
  signature_key = Ed25519::SigningKey.new("A" * 32)
  raise SelfTestFailure, "failed to generate verify key correctly" unless signature_key.verify_key.to_bytes.unpack("H*").first == "db995fe25169d141cab9bbba92baa01f9f2e1ece7df4cb2ac05190f37fcc1f9d"

  message = "crypto libraries should self-test on boot"
  signature = signature_key.sign(message)
  raise SelfTestFailure, "failed to generate correct signature" unless signature.unpack("H*").first == "c62c12a3a6cbfa04800d4be81468ef8aecd152a6a26a81d91257baecef13ba209531fe905a843e833c8b71cee04400fa2af3a29fef1152ece470421848758d0a"

  verify_key = signature_key.verify_key
  raise SelfTestFailure, "failed to verify a valid signature" unless verify_key.verify(signature, message)

  bad_signature = signature[0...63] + "X"
  ex = nil

  # rubocop:disable Lint/HandleExceptions
  begin
    verify_key.verify(bad_signature, message)
  rescue Ed25519::VerifyError => ex
  end
  # rubocop:enable Lint/HandleExceptions

  raise SelfTestFailure, "failed to detect an invalid signature" unless ex.is_a?(Ed25519::VerifyError)
end

validate_key_bytes(key_bytes) click to toggle source

Ensure a serialized key meets the requirements

# File lib/ed25519.rb, line 39
def validate_key_bytes(key_bytes)
  raise TypeError, "expected String, got #{key_bytes.class}" unless key_bytes.is_a?(String)
  return true if key_bytes.bytesize == KEY_SIZE
  raise ArgumentError, "expected #{KEY_SIZE}-byte String, got #{key_bytes.bytesize}"
end