Handbook of Applied Cryptography
Handbook of Applied Cryptography
FSE '99 Proceedings of the 6th International Workshop on Fast Software Encryption
Decrypting a Class of Stream Ciphers Using Ciphertext Only
IEEE Transactions on Computers
The bit extraction problem or t-resilient functions
SFCS '85 Proceedings of the 26th Annual Symposium on Foundations of Computer Science
EUROCRYPT'00 Proceedings of the 19th international conference on Theory and application of cryptographic techniques
FSE'07 Proceedings of the 14th international conference on Fast Software Encryption
Random permutation statistics and an improved slide-determine attack on keeloq
Cryptography and Security
Self-similarity attacks on block ciphers and application to keeloq
Cryptography and Security
Power analysis of atmel cryptomemory --- recovering keys from secure EEPROMs
CT-RSA'12 Proceedings of the 12th conference on Topics in Cryptology
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KeeLoq is a block cipher used in numerous widespread passive entry and remote keyless entry systems as well as in various component identification applications. The KeeLoq algorithm has a 64-bit key and operates on 32-bit blocks. It is based on an NLFSR with a nonlinear feedback function of 5 variables.In this paper new key recovery attacks on KeeLoq are proposed. The first one has a complexity of about 250.6KeeLoq encryptions. The second attack finds the key in 237encryptions and works for the whole key space. In our attacks we use the techniques of guess-and-determine, slide, and linear attacks as well as cycle structure analysis. Both attacks need 232known plaintext-ciphertext pairs.We also analyze the KeeLoq key management and authentication protocols applied in rolling-code and IFF access systems widely used in real-world applications. We demonstrate several practical vulnerabilities.