Crypto geeks will be delighted at Tom's latest release “Discovery of Public Key Cryptography with Whitfield Diffie’(Discovery of Public Key Cryptography with Whitfield Diffie (2015 Turing Award)' featuring Whitfield Diffie, at ease in an armchair, warmly recounting memories of the past fifty years that include his groundbreaking contributions to public-key cryptography.

While we may all be maths fans, the intricacy of each specialism, cryptography being no exception, can easily go over your head if you’ve not had the joy of studying it. But it seems a shame to miss out on fresh Tom Rocks Maths content! Here’s five things you need to know about Whitfield Diffie and his work.

  1. Where it all began..

Born in Washington D.C in 1944, Diffie was never far from the world of academia. His father, Bailey, had a doctorate degree in Iberian history which he taught at the City College of New York and his mother, Justine, was a writer and scholar. This connection to the College was one of the initial catalysts for Diffie’s passion in cryptography (as he discusses with Tom), his father often bringing him books from the college’s expansive library. When Whitfiled was just 10 years old, crypto was a common theme for these texts.

Despite the initial interest in his future field, his focus was on pure maths in the early years of his degree. While studying for his undergraduate degree at MIT, he particularly enjoyed partial differential equations and topology, only taking up computer programming as he felt the need to ‘cultivate a practical skill set’.

Aged 25, Diffie became a research programmer at the Stanford Artificial Intelligence Laboratory, working on correctness problems and LISP. His interest in cryptography and cyber security was ignited by mentor John McCarthy, a founder of the discipline of AI.

  1. But what is public key cryptography?

In cryptography, a key is a piece of information used for scrambling data so that it appears random. If you put coherent ‘plain text’ data through an algorithm that uses a key, the data comes out the other side as completely random data. With the right decryption key, it can be put back to the original data.

Public-key cryptography is a method of encrypting the data that uses two keys, a ‘public key’ that is available for anyone to use and a ‘private key’. If data has been encrypted with the public key then it can only be decrypted with the private key, and likewise if the private key is used to encrypt, only the public can decrypt.

  1. That Paper

New Directions in Cryptography is quite an understated title for a paper that solved one of the fundamental problems of cryptography. In 1976, Diffie worked with Martin Hellman to publish their ideas of this ‘dual-key’ system, a concept that revolutionised cryptography and dismantled the monopoly that had previously existed, whereby government entities controlled cryptographic technology and who could access it. Their work instead gave that power to individuals. 

  1. And now?

Since his breakthrough, Diffie has been in high demand in both business and academia. His impressive CV includes cyber security and engineering roles at top companies in California such as Northern Telecom and Sun Microsystems. In recent years he’s found his way back to universities, working as visiting professor at Royal Holloway, University of London, and currently Zhejiang University in China.

  1. Not forgetting some impressive accolades..

The most prestigious of his awards is undoubtedly the Turing Prize which he was awarded in 2015 alongside Hellman for his contributions to computer science. He has an honorary doctorate from the Swiss Institute of Technology, is a visiting fellow of the Isaac Newton Institute and in 2011 was inducted into the National Inventors Hall of Fame.