RSA Secret-Key Challenge - Contest Details

Contest Details

For each contest, RSA had posted on its website a block of ciphertext and the random initialization vector used for encryption. To win, a contestant would have had to break the code by finding the original plaintext and the cryptographic key that will generate the posted ciphertext from the plaintext. The challenge consisted of one DES contest and twelve contests based around the block cipher RC5.

Each of the RC5-* contests is named after the variant of the RC5 cipher used. The name RC5-w/r/b indicates that the cipher used w-bit words, r rounds, and a key made up of b bytes. The contests are often referred to by the names of the corresponding distributed.net projects, for example RC5-32/12/9 is often known as RC5-72 due to the 72-bit key size.

The first contest was DES Challenge III (and was also part of the DES Challenges), and was completed in just 22 hours 15 minutes by distributed.net and the EFF's Deep Crack machine.

In May 2007 RSA Laboratories announced the termination of the challenge, stating that they would not disclose the solutions to the remaining contents, and nor would they confirm or reward prize money for future solutions. On 8 September 2008 distributed.net announced that they would fund a prize of $4000 for the RC5-72 contest.