		Network Security

DES Cracked

The US Department of Defense’s Data Encryption Standard has been a target of cryptanalysts since it was first released. However, until recently, the cost of a computer system to efficiently crack DES cryptograms was prohibitive for most people and organisations. Recent advances in hardware, software and analytical methods have reduced both the cost and the time required to break a DES encrypted message.

DES draft released March 17, 1975
Many designs of DES Cracking machines
Theoretical cracker cost down from $650 m to $1 m for a key every few hours
Used by Governments, Banks, Companies
DES Cracking Contest
1998 - DIY DES Cracker from EFF
Secrets of Encryption Research, Wiretap Politics & Chip Design
Based on scientific research papers
Uses standard off-the-shelf ICs
Parallel processing techniques
Controlled by a PC
Further Information:-

DES draft released March 17, 1975

Developed from an encryption system called Lucifer from IBM. The plaintext is scrambled based on the encryption key. The key is 56 bits long. Exported products limited to 40 bit keys.

Many designs of DES Cracking machines

As soon as DES was released, academics, among others, began looking at ways to break it. Initial estimates of machine costs were very high.

Theoretical cracker cost down from $650 m to $1 m for a key every few hours

The first estimates were of the order of a half a billion dollars (in 1975 dollars!). As processing speed increased the cost estimates came down. These were for brute force software based systems.

Used by Governments, Banks, Companies

Many government, banking, financial, intelligence, military and other orgamisations use DES to encrypt their data for transmission throught their own and external networks.

DES Cracking Contest

Task set at the 1997 annual RSA Cryptographic trade show in San Francisco. 1997 - 5 months 1998 - 39 days!

1998 - DIY DES Cracker from EFF

Any encryption system can be cracked by an exhaustive search through the key space. This is the brute force method. What is significant about the EFF DES Cracker is that it reduces the question of how hard is it, to, how fast a solution can you afford!

Secrets of Encryption Research, Wiretap Politics & Chip Design

This is the book, written by members of the Electronic Frontier Foundation, published by O’Reilly.

It provides complete details of the construction of a machine for cracking DES cryptograms. The software is listed and the philosophy behind it is discussed.

The cost of the machine is about $US 200,000. Less if the labour is provided cheaply.

Based on scientific research papers

Encryption systems have always appealed to those with a penchant for solving puzzles. Mostly, this interest has been personal or academic. Many papers have been written on the subject of breaking the DES algorithm. The EFF members who built the DES Cracker based their developments on these and their own researches.

Uses standard off-the-shelf ICs

A significant part of the DES Cracker is that the actual cracking engine is built with simple (and cheap) off-the-shelf Integrated Circuits.

Parallel processing techniques

Using standard components means that scale efficiencies can be achieved at low cost. The actual process breaks the task into many discrete components that are then run simultaneously.

Controlled by a PC

The processing modules are controlled by a PC. The PC software is uncomplicated. It merely sets the tasks for the processing modules and monitors their progress. Each module tries decryption keys in sequence until it generates a possible good message. The PC program checks the possible good message and proceeds with further checks. Meanwhile the processing modules carry on cracking.

Further Information:-

EFF Web Site: http://www.eff.org O’Reilly Web Site: http://www.oreilly.com

Network Security

DES Cracked