http://dl.gi.de/handle/20.500.12116/24840 Tue, 21 Jul 2026 13:26:24 GMT 2026-07-21T13:26:24Z http://dl.gi.de:80/bitstream/id/529d9ba5-a081-4509-ae30-cc35eb7c3b43/ http://dl.gi.de/handle/20.500.12116/24840 http://dl.gi.de/handle/20.500.12116/24853 Applications of partial hiding in RSA Fhloinn, Eabhnat Ní; Purser, Michael Wulf, Christopher; Lucks, Stefan; Yau, Po-Wah We explore the possibility of exposing sections of the private key in RSA without jeopardising the security of the overall system. Making significant segments of the key publicly available greatly reduces the amount of data which must be securely hidden, allowing us to use biometric readings to protect the key. We suggest the use of iris recognition for this purpose and propose possible implementations of this scheme. Sat, 01 Jan 2005 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/24853 2005-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/24851 Related-cipher attacks on block ciphers with flexible number of rounds Sung, Jaechul; Kim, Jongsung; Lee, Changhoon; Hong, Seokhie Wulf, Christopher; Lucks, Stefan; Yau, Po-Wah Related-cipher attack was introduced by Hongjun Wu in 2002 [25]. We can consider related ciphers as block ciphers with the same round function but different number of rounds. This attack can be applied to related ciphers by using the fact that their key schedules do not depend on the total number of rounds. In this paper we introduce differential related-cipher attack on block ciphers, which combine related- cipher attack with differential cryptanalysis. We apply this attack to the block ciphers ARIA [15] and SC2000 [24]. Furthermore, related-cipher attack can be combined with other block cipher attacks such as linear cryptanalysis, higher-order differential crypt- analysis, and so on. With these combined attacks we also analyze some other block ciphers which use flexible number of rounds, SAFER++, CAST-128 and DEAL. Sat, 01 Jan 2005 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/24851 2005-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/24852 Collision attacks on processors with cache and countermeasures Lauradoux, Cédric Wulf, Christopher; Lucks, Stefan; Yau, Po-Wah Implementing cryptographic algorithms is a difficult problem since additional secret information can be recovered from some physical characteristics of a cryptographic device. Among all side-channel attacks, collision attacks and cache attacks are the most recent ones. The first technique uses side-channel information to detect internal collisions related to the algorithm. The second one exploits timing or power consumptions related to the memory accesses. This paper presents a new attack on the first round of AES based on power analysis, which combines both collision attacks and cache attacks. It provides many linear relations between the secret key bits from the encryption of a few chosen plaintexts. For instance, for a classical implementation using 4 lookup tables on a processor with 64-byte cache blocks, 48 linear relations involving half of the key bits are derived. Some countermeasures which defeat such attacks are also presented. Sat, 01 Jan 2005 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/24852 2005-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/24850 State recovery attacks on pseudorandom generators Sidorenko, Andrey; Schoenmakers, Berry Wulf, Christopher; Lucks, Stefan; Yau, Po-Wah State recovery attacks comprise an important class of attacks on pseudorandom generators. In this paper we analyze resistance of pseudorandom generators against these attacks in terms of concrete security. We show that security of the Blum- Micali pseudorandom generator against state recovery attacks is tightly related to the security of the corresponding one-way function. Sat, 01 Jan 2005 00:00:00 GMT http://dl.gi.de/handle/20.500.12116/24850 2005-01-01T00:00:00Z