refactor: use WebAuthn::PublicKey on assertion

lib/webauthn/authenticator_assertion_response.rb

@@ -2,11 +2,11 @@
 
 require "cose/algorithm"
 require "cose/key"
-require "webauthn/attestation_statement/fido_u2f/public_key"
 require "webauthn/authenticator_data"
 require "webauthn/authenticator_response"
 require "webauthn/encoder"
 require "webauthn/signature_verifier"
+require "webauthn/public_key"
 
 module WebAuthn
  class SignatureVerificationError < VerificationError; end
@@ -42,7 +42,7 @@ def initialize(authenticator_data:, signature:, user_handle: nil, **options)
  def verify(expected_challenge, expected_origin = nil, public_key:, sign_count:, user_verification: nil,
  rp_id: nil)
  super(expected_challenge, expected_origin, user_verification: user_verification, rp_id: rp_id)
- verify_item(:signature, credential_cose_key(public_key))
+ verify_item(:signature, WebAuthn::PublicKey.deserialize(public_key))
  verify_item(:sign_count, sign_count)
 
  true
@@ -56,9 +56,9 @@ def authenticator_data
 
  attr_reader :authenticator_data_bytes, :signature
 
- def valid_signature?(credential_cose_key)
+ def valid_signature?(webauthn_public_key)
  WebAuthn::SignatureVerifier
- .new(credential_cose_key.alg, credential_cose_key.to_pkey)
+ .new(webauthn_public_key.cose_key.alg, webauthn_public_key.pkey)
  .verify(signature, authenticator_data_bytes + client_data.hash)
  end
 
@@ -71,29 +71,6 @@ def valid_sign_count?(stored_sign_count)
  end
  end
 
- def credential_cose_key(public_key)
- if WebAuthn::AttestationStatement::FidoU2f::PublicKey.uncompressed_point?(public_key)
- # Gem version v1.11.0 and lower, used to behave so that Credential#public_key
- # returned an EC P-256 uncompressed point.
- #
- # Because of https://github.com/cedarcode/webauthn-ruby/issues/137 this was changed
- # and Credential#public_key started returning the unchanged COSE_Key formatted
- # credentialPublicKey (as in https://www.w3.org/TR/webauthn/#credentialpublickey).
- #
- # Given that the credential public key is expected to be stored long-term by the gem
- # user and later be passed as the public_key argument in the
- # AuthenticatorAssertionResponse.verify call, we then need to support the two formats.
- COSE::Key::EC2.new(
- alg: COSE::Algorithm.by_name("ES256").id,
- crv: 1,
- x: public_key[1..32],
- y: public_key[33..-1]
- )
- else
- COSE::Key.deserialize(public_key)
- end
- end
-
  def type
  WebAuthn::TYPES[:get]
  end