# File lib/aws/core/authorize_v3.rb, line 27
      def add_authorization! signer
        self.access_key_id = signer.access_key_id
        parts = []
        parts << "AWS3-HTTPS AWSAccessKeyId=#{access_key_id}"
        parts << "Algorithm=HmacSHA256"
        parts << "Signature=#{signer.sign(string_to_sign)}"
        headers['x-amzn-authorization'] = parts.join(',')
      end