DEAL

DEAL

Round function of DEAL
General
Designers	Lars Knudsen
First published	1998
Derived from	DES
Related to	Ladder-DES
Cipher detail
Key sizes	128, 192 or 256 bits
Block sizes	128 bits
Structure	Nested Feistel network
Rounds	6 (128- and 192-bit key) or 8 (256-bit key)

In cryptography, DEAL (Data Encryption Algorithm with Larger blocks) is a block cipher derived from the Data Encryption Standard (DES). The design was proposed in a report by Lars Knudsen in 1998, and was submitted to the AES contest by Richard Outerbridge (who notes that Knudsen had presented the design at the SAC conference in 1997).

DEAL is a Feistel network which uses DES as the round function. It has a 128-bit block size and a variable key size of either 128, 192, or 256 bits. For key sizes of 128 and 192 bits, the cipher uses 6 rounds, increasing to 8 for the 256-bits size. The scheme has a comparable performance to Triple DES, and was relatively slow compared to many other AES candidates.

See also

• Ladder-DES
• Luby-Rackoff

External links

• The original DEAL report
• SCAN's entry for DEAL
• AES presentation slides (PDF)

References

• John Kelsey, Bruce Schneier (August 1999). "Key-Schedule Cryptanalysis of DEAL" (PDF/PostScript). 6th Annual International Workshop on Selected Areas in Cryptography (SAC '99). Kingston, Ontario: Springer-Verlag. pp. 118–134. http://www.schneier.com/paper-deal.html. Retrieved 2007-08-23. 
• Stefan Lucks: On Security of the 128-Bit Block Cipher DEAL. Fast Software Encryption 1999: 60–70