DEAL - Definition and Overview

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 (http://www.mat.dtu.dk/people/Lars.R.Knudsen/newblock.html)
• SCAN's entry for DEAL (http://www.users.zetnet.co.uk/hopwood/crypto/scan/cs.html#DEAL)
• AES presentation slides (http://csrc.nist.gov/CryptoToolkit/aes/round1/conf1/deal-slides.pdf) (PDF)

References

• John Kelsey, Bruce Schneier: Key-Schedule Cryptanalysis of DEAL. Selected Areas in Cryptography 1999: 118–134
• Stefan Lucks: On Security of the 128-Bit Block Cipher DEAL. Fast Software Encryption 1999: 60–70