TPP: The Two-Way Password Protocol

The need for secure communication in the Internet has led to the widespread deployment of secure application-level protocols. The current state- of-the-art is to use TLS, in conjunction with a password protocol. The password protocol, which we call a one-way password protocol (OPP), authenticates a user to a server, using a particular secret called the password. TLS has two functions: (1) It ensures secure communication between a client and a server (2) It allows a user to authenticate a server. The first function effectively provides a secure channel for end-to- end communication between a client and a server. However, the second function is frequently compromised by a variety of Phishing attacks. In this paper, we address this problem by developing a password protocol which we name the Two-way Password Protocol (TPP). TPP, when used in conjunction with TLS, ensures that users correctly authenticate servers, and are protected from Phishing attacks. The first contribution of this paper is to develop a protocol, called the Universal Password Protocol (UPP), which ensures that a user´s password is kept safe even in the case of a successful Phishing attack. However, it may be noted that a user, after logging in, frequently shares other secrets (such as credit card number) over the secure connection, and UPP cannot protect these. Our second contribution is to build on UPP and develop, first, the Two-Way Password Protocol (TPP), and finally an improved version named the Dynamic Two-Way Password Protocol (DTPP), which ensures that both a server and a client are properly authenticated to each other. This ensures the security of all secrets which should be known only to the client and the server, including, of course, the password.