You're reading: Posts By Christian Lawson-Perfect

GCHQ has declassified James Ellis’s papers on public key cryptography

secret-squirrel-gchq

Robert Hannigan, the Director of British intelligence agency GCHQ, gave a speech at MIT recently on the currently contentious issue of backdoors into encryption.

To accompany his speech, and maybe to reaffirm GCHQ’s credentials on the subject, he published two papers written by James Ellis in 1970 about what would become public key encryption: “The Possibility of Secure Non-Secret Digital Encryption” and “The Possibility of Secure Non-Secret Analogue Encryption”.

The story famously goes that two decades after Rivest, Shamir and Adleman announced the RSA algorithm for public key cryptography, GCHQ admitted that their employee Clifford Cocks had come up with essentially the same thing four years before, inspired by James Ellis’s papers on the possibility of cryptography without a secret key.

More information

Rober Hannigan’s speech, Front doors and strong locks: encryption, privacy and intelligence gathering in the digital era.

Read the papers: “The Possibility of Secure Non-Secret Digital Encryption” and “The Possibility of Secure Non-Secret Analogue Encryption” by James Ellis.

Ohioans measure a really big π

20160312_140500

Ohio State University mathematician Niles Johnson got in touch on Friday to tell us that our π Approximation Challenge last year had inspired him to hatch an audacious plan to measure a really big π.

The word ‘geometry’ is derived from the Greek for ‘measurement of land’, and Dr. Johnson took that quite literally: he wanted to measure the Great Circle Earthworks in Heath, Ohio; a part of the Newark Earthworks (not their original name) built over 2,000 years ago.

I bought isthisprime.com

probable prime

Around about exactly this time a year ago, I bought the frivolous domain name three.onefouronefivenine.com, to celebrate π Day and to indulge my curiosity about a marvellous algorithm to compute π’s digits.

This year, I’ve been thinking about prime numbers, and my hosting provider has run another sale on domain names. So, I’ve bought isthisprime.com. You can probably guess what I’ve made it do.

Maths Objects: polyhedra

Time for some more maths objects! This time I wanted to show you the various polyhedra I’ve got around my desk.