In 1998 the Electronic Frontier Foundation (EFF)  built a machine to crack DES by exhaustive key search. This machine was used to solve the RSA DES II Challenge Contest  in less than 3 days. Total cost to design the machine was less than $250.000.
The motivation for this project and the design of the DES Cracker are described in the book `Cracking DES, Secrets of Encryption Research, Wiretap Politics & Chip Design' .
This book also contains full source code listings that were used in the design. However, this code was developed in the USA and cryptography export controls forbid the export of these documents in electronic form.
The COSIC research group of the KU Leuven  has taken the initiative to scan in the source code from  as given in Chapters 5, 6 and 7. (The EFF had encouraged this by publishing these documents in a format that made scanning `easier'.) For this the PGP OCR tools  were used. Thus, the electronic versions of the DES Cracker source code are now available to the cryptographic community outside the USA.
Download the DES Cracker source code here.
Feedback and comments can be sent to firstname.lastname@example.org.
 `Cracking DES, Secrets of Encryption Research, Wiretap Politics & Chip
Design', Electronic Frontier Foundation, O'Reilly & Associates, Sebastopol,
COSIC research group
Department of Electrical Engineering
Katholieke Universiteit Leuven