EFF DES Cracker - The DES Challenges

The DES Challenges

Since DES was a federal standard, the US government encouraged the use of DES for all non-classified data. RSA Security wished to demonstrate that DES's key length was not enough to ensure security, so they set up the DES Challenges in 1997, offering a monetary prize. The first DES Challenge was solved in 96 days by the DESCHALL Project led by Rocke Verser in Loveland, Colorado. RSA Security set up DES Challenge II-1, which was solved by distributed.net in 41 days in January and February 1998.

In 1998, the EFF built Deep Crack for less than $250,000. In response to DES Challenge II-2, on July 17, 1998, Deep Crack decrypted a DES-encrypted message after only 56 hours of work, winning $10,000. This was the final blow to DES, against which there were already some published cryptanalytic attacks. The brute force attack showed that cracking DES was actually a very practical proposition. For most governments or corporations, building a machine like Deep Crack would pose little problems.

Six months later, in response to RSA Security's DES Challenge III, and in collaboration with distributed.net, the EFF used Deep Crack to decrypt another DES-encrypted message, winning another $10,000. This time, the operation took less than a day — 22 hours and 15 minutes. The decryption was completed on January 19, 1999. In October of that year, DES was reaffirmed as a federal standard, but this time the standard recommended Triple DES.

The small key-space of DES, and relatively high computational costs of Triple DES resulted in its replacement by AES as a Federal standard, effective May 26, 2002.