- ICE (cipher)
Infobox block cipher
name = ICE
caption = The ICE Feistel function
designers = Matthew Kwan
publish date = 1997
derived from = DES
derived to =
key size = 64 bits (ICE), 64×"n" bits (ICE-"n")
block size = 64 bits
structure =Feistel network
rounds = 16 (ICE), 8 (Thin-ICE), 16×"n" (ICE-"n")
cryptanalysis =Differential cryptanalysis can break 15 out of 16 rounds of ICE with complexity 256. Thin-ICE can be broken using 227 chosen plaintexts with a success probability of 95%.In
cryptography , ICE (Information Concealment Engine) is ablock cipher published by Kwan in 1997. The algorithm is similar in structure to DES, but with the addition of a key-dependent bit permutation in the round function. The key-dependent bit permutation is implemented efficiently in software. The ICE algorithm is not subject to patents, and the source code has been placed into the public domain.ICE is a
Feistel network with a block size of 64 bits. The standard ICE algorithm takes a 64-bit key and has 16 rounds. A fast variant, Thin-ICE, uses only 8 rounds. An open-ended variant, ICE-"n", uses 16"n" rounds with 64"n" bit key.Van Rompay et al (1998) attempted to apply
differential cryptanalysis to ICE. They described an attack on Thin-ICE which recovers the secret key using 223chosen plaintext s with a 25% success probability. If 227 chosen plaintexts are used, the probability can be improved to 95%. For the standard version of ICE, an attack on 15 out of 16 rounds was found, requiring 256 work and at most 256 chosen plaintexts.References
* Matthew Kwan, The Design of the ICE Encryption Algorithm, Fast Software Encryption 1997, pp69–82 [http://www.darkside.com.au/ice/paper.html] .
* Bart van Rompay, Lars R. Knudsen and Vincent Rijmen, Differential Cryptanalysis of the ICE Encryption Algorithm, Fast Software Encryption 1998, pp270–283 [http://www.cosic.esat.kuleuven.ac.be/publications/article-120.pdf (PDF)] .External links
* [http://www.darkside.com.au/ice/index.html The ICE Home Page]
* [http://www.darkside.com.au/ice/slides/slide01.htm The ICE information slides]
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