Here we introduce the M-Pin client-server protocol, which features two-factor client authentication as an alternative to Username/Password. Despite the mathematical complexity of the protocol we demonstrate that an M-Pin client can be implemented in an environment with limited computational capability. Download this paper on M-Pin Authentication Protocol 1 Executive Summary The M-Pin protocol is intended to replace the well-known Username/Password authentication mechanism which is widely considered to be effectively broken. The main problem is the existence of a “password file” on the server, which is commonly stolen and hacked, revealing most user passwords.…