Computer Security and Cryptography

9.11 THE EFS DES-CRACKER

IBM's submitted DES in response to the National Bureau of Standards request in the Federal Register of August 27, 1974, for a national data encryption standard. After the publication in DES in March 1975, two workshops on DES were organized, the second to review the cryptanalysis effort on DES. There were three contentious areas:

1. Did DES contain any hidden trap doors whose knowledge might permit the decipherment of DES ciphertext without the key?
2. What design principles were used in DES?
3. Why was the key length chosen to be 56 bits?

Very few answers were forthcoming. IBM does business throughout the world and feels itself required to abide by the wishes of the U.S. Government. In any event 2⁵⁶ = 72,057,594,037,927,936 seemed like to large a number of key trial and the cost of building a machine required to perform key trial seemed to make the possibility remote.

A practical architecture for a DES-cracker with custom chips was proposed in 1993 by Michael Wiener of Bell Northern Research [Wiener, 1993]. The Electronic Frontier Foundation (EFF) founded in 1990 is a nonprofit public-interest group of “passionate people lawyers, technologists, volunteers, and visionaries working to protect your digital rights.” The EFF seeks to educate individuals, organizations, companies, and governments about the issues that arise when computer and communications technologies change. The EFF sponsored the design and assembling of a DES-cracker [EFF, 1998].

Figure 9.11 A ...