The Twofish Encryption Algorithm: A 128-Bit Block CipherThe first and only guide to one of today's most important new cryptography algorithms The Twofish Encryption Algorithm A symmetric block cipher that accepts keys of any length, up to 256 bits, Twofish is among the new encryption algorithms being considered by the National Institute of Science and Technology (NIST) as a replacement for the DES algorithm. Highly secure and flexible, Twofish works extremely well with large microprocessors, 8-bit smart card microprocessors, and dedicated hardware. Now from the team who developed Twofish, this book provides you with your first detailed look at: * All aspects of Twofish's design and anatomy * Twofish performance and testing results * Step-by-step instructions on how to use it in your systems * Complete source code, in C, for implementing Twofish On the companion Web site you'll find: * A direct link to Counterpane Systems for updates on Twofish * A link to the National Institute of Science and Technology (NIST) for ongoing information about the competing technologies being considered for the Advanced Encryption Standard (AES) for the next millennium For updates on Twofish and the AES process, visit these sites: * www.wiley.com/compbooks/schneier * www.counterpane.com * www.nist.gov/aes Wiley Computer Publishing Timely.Practical.Reliable Visit our Web site at www.wiley.com/compbooks/ Visit the companion Web site at www.wiley.com/compbooks/schneier |
From inside the book
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... LP max Over All Keys . Table 7.2 shows the distribution of LPmax for the various key sizes . Observe that the vast majority of Twofish S- boxes have LPmax < ( 88/256 ) 2 , although there is a small fraction of S - boxes with larger ...
... LP max Over All Keys . Table 7.2 shows the distribution of LPmax for the various key sizes . Observe that the vast majority of Twofish S- boxes have LPmax < ( 88/256 ) 2 , although there is a small fraction of S - boxes with larger ...
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A 128-Bit Block Cipher Bruce Schneier. - log2 ( Pr ( LPmax = ( x / 256 ) 2 ) ) Key size 128 bits Max Value ( 100/256 ) ... LP max Over All Keys . Key Size Max Value x = 0 1 128 bits 8 192 bits 10 256 bits * random 10 — log2 ( Pr ( # fixed ...
A 128-Bit Block Cipher Bruce Schneier. - log2 ( Pr ( LPmax = ( x / 256 ) 2 ) ) Key size 128 bits Max Value ( 100/256 ) ... LP max Over All Keys . Key Size Max Value x = 0 1 128 bits 8 192 bits 10 256 bits * random 10 — log2 ( Pr ( # fixed ...
Page 101
... LP max ( 108/256 ) 2 , so this suggests an < attacker would need at least ( LPmax ) -36≈ 289.6 known plaintexts ; and such an analysis would only work for a very small class of weak keys ( representing about 2-49.6 of the keyspace for ...
... LP max ( 108/256 ) 2 , so this suggests an < attacker would need at least ( LPmax ) -36≈ 289.6 known plaintexts ; and such an analysis would only work for a very small class of weak keys ( representing about 2-49.6 of the keyspace for ...
Common terms and phrases
16 rounds 2-round 32-bit words active S-boxes addition Advances in Cryptology analysis bits of key block cipher Blowfish byte sequences chosen plaintexts ciphertext clock cycles compute Counterpane Systems CPUs cryptographic define difference sequence differential attack differential characteristic Differential Cryptanalysis differential patterns differential probabilities DWORD Encryption Algorithm encryption and decryption endif F function family key Fast Software Encryption Feistel network fixed S-boxes four S-boxes Hamming weight hardware hash function implementations input difference International Workshop Proceedings key bytes key length key material key schedule key setup key sizes key-dependent S-boxes keyLen linear cryptanalysis MDS matrix MDS matrix multiply number of rounds outBuffer output difference pair of keys Pentium Pentium Pro performance permutations possible PPro/II precomputed properties q₁ random related-key attack right pair round function round subkeys smart cards speed Springer-Verlag Table Twofish Twofish variant weak keys whitening XOR difference XORed zero