Roger Needham

Recently, we lost a great leader in cryptography: Ross Anderson [here]. Ross had the privilege to have Roger Needham as his PhD supervisor, and who was a world-leading researcher in security, operating systems, computer architecture and networking. In 2005, the two of them wrote a classic paper of “Programming Satan’s Computer” [here][4]:

At the age of 68, Roger died on 1 March 2003. Let’s look at a few of Roger’s research advancements.

Needham Schroeder protocol

Roger, along with Michael Schroeder, defined a method which created a trust infrastructure for key management [1]. Overall public key methods are not the only way to negotiate a key. For this, we can use a symmetric key method, and where Bob and Alice can generate a shared encryption key. We then need a KDC (Key Distribution Centre) to enable the sharing.In this case, the KDC (Trent) holds Alice and Bob’s long-term symmetric key (Ka and Kb). Initially, Alice asks the KDC if she wants to speak with Bob. The KDC then creates the session key of KS and then encrypts this key and Alice’s ID with Bob key, and then adds this onto the session key and Bob’s ID, and then encrypts the whole lot with Alice’s key: