Contents

require 'openssl'

module SignedForm
  module HMAC
    extend self

    attr_accessor :secret_key

    def create_hmac(data)
      if secret_key.nil? || secret_key.empty?
        raise Errors::NoSecretKey, "Please consult the README for instructions on creating a secret key"
      end

      OpenSSL::HMAC.hexdigest OpenSSL::Digest::SHA1.new, secret_key, data
    end

    def verify_hmac(signature, data)
      if secret_key.nil? || secret_key.empty?
        raise Errors::NoSecretKey, "Please consult the README for instructions on creating a secret key"
      end

      secure_compare OpenSSL::HMAC.hexdigest(OpenSSL::Digest::SHA1.new, secret_key, data), signature
    end

    # After the Rack implementation
    def secure_compare(a, b)
      return false unless a.bytesize == b.bytesize

      l = a.unpack("C*")

      r, i = 0, -1
      b.each_byte { |v| r |= v ^ l[i+=1] }
      r == 0
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
signed_form-0.0.1	lib/signed_form/hmac.rb