Allen works as a Software Developer for ManSoft Inc. The company uses Visual Studio.NET as its application development platform. He creates an application. He wants to allow remote users to connect and access the application through a dial-up connection via the Internet. All data will be sent across a public network. For security reasons, the management wants to send data through the Internet in an encrypted form. The company plans to use a Layer 2 Tunneling Protocol (L2TP) connection. Which of the following communication protocols will Allen use to accomplish the task?