  In the thesis we focus on designing an authentication system to authenticate
users over a network with a username and a password. The system uses the
zero-knowledge proof (ZKP) system as a password verification mechanism. The ZKP
protocol used is based on the quadratic residuosity problem. The authentication
system is defined as a method in the extensible authentication protocol (EAP).
Using a ZKP system yields interesting security properties that make the system
favourable to be used over insecure networks.
