# File lib/oauth2/mac_token.rb, line 80
    def signature(timestamp, nonce, verb, uri)
      signature = [
        timestamp,
        nonce,
        verb.to_s.upcase,
        uri.request_uri,
        uri.host,
        uri.port,
        '', nil
      ].join("\n")

      strict_encode64(OpenSSL::HMAC.digest(@algorithm, secret, signature))
    end