On the weak keys of blowfish
- Serge Vaudenay
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Blowfish is a sixteen-rounds Feistel cipher in which the F function is a part of the private key. In this paper, we show that the disclosure of F allows to perform a differential cryptanalysis which can recover all the rest of the key with 248 chosen plaintexts against a number of rounds reduced to eight. Moreover, for some weak F function, this attack only needs 223 chosen plaintexts against eight rounds, and 3×251 chosen plaintexts against sixteen-rounds. When the F function is safely kept private, one can detect whether it is weak or not with a differential attack using 222 plaintexts against eight rounds.
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- On the weak keys of blowfish
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- Fast Software Encryption
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- Third International Workshop Cambridge, UK, February 21–23 1996 Proceedings
- pp 27-32
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- Lecture Notes in Computer Science
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- Springer Berlin Heidelberg
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