Differential cryptanalysis of the data encryption standard
Differential cryptanalysis of the data encryption standard
Linear cryptanalysis method for DES cipher
EUROCRYPT '93 Workshop on the theory and application of cryptographic techniques on Advances in cryptology
Truncated Differentials of SAFER
Proceedings of the Third International Workshop on Fast Software Encryption
Truncated Differentials and Skipjack
CRYPTO '99 Proceedings of the 19th Annual International Cryptology Conference on Advances in Cryptology
FSE '99 Proceedings of the 6th International Workshop on Fast Software Encryption
Saturation Attacks on Reduced Round Skipjack
FSE '02 Revised Papers from the 9th International Workshop on Fast Software Encryption
A Cryptanalytic View of the NSA's Skipjack Block Cipher Design
ISA '09 Proceedings of the 3rd International Conference and Workshops on Advances in Information Security and Assurance
Practical attack on 8 rounds of the lightweight block cipher KLEIN
INDOCRYPT'11 Proceedings of the 12th international conference on Cryptology in India
Hi-index | 0.00 |
Skipjack is the secret key encryption algorithm developed by the NSA for the Clipper chip and Fortezza PC card. It uses an 80-bit key, 128 table lookup operations, and 320 XOR operations to map a 64- bit plaintext into a 64-bit ciphertext in 32 rounds. This paper describes an efficient attack on a variant, which we call Skipjack-3XOR (Skipjack minus 3 XORs). The only difference between Skipjack and Skipjack- 3XOR is the removal of 3 out of the 320 XOR operations. The attack uses the ciphertexts derived from about 500 plaintexts and its total running time is equivalent to about one million Skipjack encryptions, which can be carried out in seconds on a personal computer. We also present a new cryptographic tool, which we call the Yoyo game, and efficient attacks on Skipjack reduced to 16 rounds. We conclude that Skipjack does not have a conservative design with a large margin of safety.