The Colossus Mk2, a wartime code-breaker that helped to turn the course of World War II, has successfully been rebuilt and is now on display at Bletchley Park, the hub of British code operations. The original Colossus played a key role in deciphering the Lorenz code used by Hitler. It was destroyed along with nine other Colossus machines after the end of the war.

The Colossus rebuild project began in 1993 using photos and illegally kept diagrams. The working replica is capable of breaking the same ciphers it cracked during the war and was unveiled to veteran coders in June, 2004 to mark the 60 th anniversary of the first time the switch was flipped.

For more information on the project itself, visit:

William Tutte, one of the researchers whose work led to the development of the Colossus, was profiled in the first issue of Code and Cipher.

Crypto Challenges Solved

On April 27, 2004, RSA Security Inc. and Certicom Corp. both announced winners of cryptographic challenges. The challenges were each started as a way to stimulate further research in the security analysis of cryptosystems and increase industry understanding and appreciation for the strength of a variety of key size levels.

The RSA-576 Factoring Challenge was to determine the two prime factors of a number that is 576 bits in length. The security of RSA with a 576-bit modulus is based on the difficulty of factoring such numbers. A multinational team of eight experts used about 100 workstations to factor this number in about 3 months.

The Certicom (ECC)2-109 bit challenge was solved by Chris Monico, an assistant professor at Texas Tech University and a team of mathematicians. Their effort required 2600 computers and took 17 months.

A prize of $10,000 US was awarded in each of the challenges. Both of these strengths are well below the crypto that is used commercially today.

For more information about the Certicom ECC challenge, visit: