In this section the most relevant identity management systems are introduced briefly.

Idemix. “Identity Mixer (idemix) is an anonymous credential system developed at IBM Research that enables strong authentication and privacy at the same time.”

Kerberos. “Kerberos is a network authentication protocol. It is designed to provide strong authentication for client/server applications by using secret-key cryptography.”

Liberty Alliance. “The vision of Liberty Alliance is to enable a networked world based on open standards where consumers, citizens, businesses and governments can more easily conduct online transactions while protecting the privacy and security of identity information.”

PrimeLife. “[PrimeLife's] long-term vision is to counter the trend to life-long personal data trails without compromising on functionality.”