Sponge function

About: Sponge function is a research topic. Over the lifetime, 159 publications have been published within this topic receiving 3919 citations.

A MAC Forgery Attack on SOBER-128 *

Abstract: SOBER-128 is a stream cipher designed by Rose and Hawkes in 2003. It can be also used for generating Message Authentication Codes (MACs) and an authenticated encryption. The developers claimed that it is diffcult to forge MACs generated by both functions of SOBER-128, though, the security assumption in the proposal paper is not realistic in some instances. In this paper, we examine the security of these message authentication mechanisms of SOBER-128 under security channel model. As a result, we show that both a MAC generation and an authenticated encryption are vulnerable against differential cryptanalysis. The success probabilities of the MAC forgery attack are estimated at 2-6 and 2-27 respectively. In addition, we show that some secret bits are revealed if a key is used many times.

Cryptography for network security: failures, successes and challenges

Abstract: This article discusses the state of the art of cryptographic algorithms as deployed for securing computing networks. While it has been argued that the design of efficient cryptographic algorithms is the "easy" part of securing a large scale network, it seems that very often security problems are identified in algorithms and their implementations.

A general encryption scheme based on MDS code

Abstract: In this paper, we propose to combine cryptographically strong random key stream generators (including those used in stream ciphers) with simple block encoders to achieve both high cryptographic strength and low computation complexity of encryption and decryption. In particular, we show proper error-correcting codes can be used as block encoders. In general, encoding and decoding of a proper block error (or more accurately erasure) correcting code is much faster than encryption and decryption of block ciphers.

Cryptographic Properties of Stream Ciphers Based on T-functions

Abstract: The cryptographic properties of keystreams that are generated by stream ciphers based on T-functions are studied in this paper. Such constructions, which have been lately proposed by Klimov and Shamir, are of great interest as they allow building efficient and secure cryptographic primitives. By using concepts from the analysis of sequences, namely the linear complexity, we are able to derive simple linear equations of small weight satisfied by all T-functions. This indicates the non-randomness exhibited by state sequences produced from such mappings. Furthermore, we consider the particular class of algebraic T-functions and give necessary and sufficient conditions to generate a single cycle.

Sponge Based CCA2 Secure Asymmetric Encryption for Arbitrary Length Message

Abstract: OAEP and other similar schemes proven secure in Random-Oracle Model require one or more hash functions with output size larger than those of standard hash functions. In this paper, we show that by utilizing popular Sponge constructions in OAEP framework, we can eliminate the need of such hash functions. We provide a new scheme in OAEP framework based on Sponge construction and call our scheme Sponge based asymmetric encryption padding (SpAEP). SpAEP is based on 2 functions: Sponge and SpongeWrap, and requires only standard output sizes proposed and standardized for Sponge functions. Our scheme is CCA2 secure for any trapdoor one-way permutation in the ideal permutation model for arbitrary length messages. Our scheme utilizes the versatile Sponge function to enhance the capability and efficiency of the OAEP framework. SpAEP with any trapdoor one-way permutation can also be used as a key encapsulation mechanism and a tag-based key encapsulation mechanism for hybrid encryption. Our scheme SpAEP utilizes the permutation model efficiently in the setting of public key encryption in a novel manner.