# frozen_string_literal: true require "cose/algorithm/base" require "cose/error" module COSE module Algorithm class SignatureAlgorithm < Base def verify(key, signature, verification_data) compatible_key?(key) || raise(COSE::Error, "Incompatible key for signature verification") valid_signature?(key, signature, verification_data) || raise(COSE::Error, "Signature verification failed") end def compatible_key?(key) valid_key?(key) && to_pkey(key) rescue COSE::Error false end private def valid_signature?(key, signature, verification_data) signature_algorithm = signature_algorithm_class.new(hash_function[3..-1]) signature_algorithm.verify_key = to_pkey(key) begin signature_algorithm.verify(signature, verification_data) rescue OpenSSL::SignatureAlgorithm::Error false end end def to_cose_key(key) case key when COSE::Key::Base key when OpenSSL::PKey::PKey COSE::Key.from_pkey(key) else raise(COSE::Error, "Don't know how to transform #{key.class} to COSE::Key") end end def signature_algorithm_class raise NotImplementedError end def valid_key?(_key) raise NotImplementedError end def to_pkey(_key) raise NotImplementedError end end end end