Infinite length hash chains and their applications

Bicakci, K
Baykal, Nazife
Hash Chains are used extensively in various cryptography, applications such as one-time passwords, server-supported signatures and micropayments. In this paper, we present a method, called Infinite Length Hash Chains to improve the flexibility of this chaining idea by using public-key techniques. One of its distinguishing features is that communication and computation overhead of restarting of the system is avoided. For the owner of the chain it is possible to go in either way in the chain at any time without any restriction in the chain length, but others see no difference as the functionality it provides with respect to traditional hash chains. On the other hand the drawback here is the increased computation cost due to public-key operations. Part of our work would be considered as one additional step after traditional one-time passwords in the natural progression from fixed password schemes to challenge response identification protocols.


Efficient multivariate-based ring signature schemes
Demircioğlu, Murat; Cenk, Murat; Akleylek, Sedat; Department of Cryptography (2022-8-4)
The ring signature scheme has a wide range of usage areas in public-key cryptography. One is leaking information within a group without exposing the signer's identity. The majority of the ring signature techniques in use, on the other hand, rely on classical crypto-systems such as RSA and ECDH, which are known to be vulnerable to Shor's algorithm on a large-scale quantum computer. In this thesis, we propose efficient quantum-resistant ring signature schemes based on GeMSS and Gui signature algorithms. Gui w...
Design and analysis of hash functions
Koçak, Onur; Doğanaksoy, Ali; Department of Cryptography (2009)
Hash functions are cryptographic tools that are used in various applications like digital signature, message integrity checking, password storage and random number generation. These cryptographic primitives were, first, constructed using modular arithmetical operations which were popular at that time because of public key cryptography. Later, in 1989, Merkle and Damgard independently proposed an iterative construction method. This method was easy to implement and had a security proof. MD-4 was the first has...
Improved server assisted signatures
Bicakci, K; Baykal, Nazife (2005-02-21)
It is well known that excessive computational demands of public key cryptography have made its use limited especially when constrained devices are of concern. To reduce the costs of generating public key signatures one viable method is to employ a third party; the server. In open networks, getting help from a verifiable-server has an advantage over proxy-based solutions since as opposed to proxy-server, verifiable-server's cheating can be proven.
Truncated Impossible and Improbable Differential Analysis of ASCON
Tezcan, Cihangir (2016-02-01)
Ascon is an authenticated encryption algorithm which is recently qualified for the second-round of the Competition for Authenticated Encryption: Security, Applicability, and Robustness. So far, successful differential, differential-linear, and cube-like attacks on the reduced-round Ascon are provided. In this work, we provide the inverse of Ascon's linear layer in terms of rotations which can be used for constructing impossible differentials. We show that Ascon's S-box contains 35 undisturbed bits and we us...
Results on characterizations of plateaued functions in arbitrary characteristic
Mesnager, Sihem; Özbudak, Ferruh; Sınak, Ahmet (2016-01-01)
Bent and plateaued functions play a significant role in cryptography since they can have various desirable cryptographic properties. In this work, we first provide the characterizations of plateaued functions in terms of the moments of their Walsh transforms. Next, we generalize the characterizations of Boolean bent and plateaued functions in terms of their second-order derivatives to arbitrary characteristic. Moreover, we present a new characterization of plateaued functions in terms of fourth power moment...
Citation Formats
K. Bicakci and N. Baykal, “Infinite length hash chains and their applications,” 2002, Accessed: 00, 2020. [Online]. Available: