Security audit in cloud-based server by using encrypted data AES -256 and SHA-256

Security Level of Cryptography – SHA - 256

Attacking Reduced Round SHA-256

The SHA-256 hash function has started getting attention recently by the cryptanalysis community due to the various weaknesses found in its predecessors such as MD4, MD5, SHA-0 and SHA-1. We make two contributions in this work. First we describe message modification techniques and use them to obtain an algorithm to generate message pairs which collide for the actual SHA-256 reduced to 18 steps. ...

Analysis of SHA-512/224 and SHA-512/256

In 2012, NIST standardized SHA-512/224 and SHA-512/256, two truncated variants of SHA-512, in FIPS 180-4. These two hash functions are faster than SHA-224 and SHA-256 on 64-bit platforms, while maintaining the same hash size and claimed security level. So far, no third-party analysis of SHA-512/224 or SHA-512/256 has been published. In this work, we examine the collision resistance of step-redu...

Analysis of Step-Reduced SHA-256

This is the first article analyzing the security of SHA-256 against fast collision search which considers the recent attacks by Wang et al. We show the limits of applying techniques known so far to SHA-256. Next we introduce a new type of perturbation vector which circumvents the identified limits. This new technique is then applied to the unmodified SHA-256. Exploiting the combination of Boole...

Analysis of a SHA-256 Variant

SHA-256 is a cryptographic hash function which was proposed in 2000 as a new generation of SHA functions and was adopted as FIPS standard in 2002. In this paper we will consider a SHA-256 variant and a SHACAL-2 variant in which every arithmetic addition is replaced by XOR operation. We call the SHA-256 variant SHA-2-XOR and the SHACAL-2 variant SHACAL-2-XOR respectively. We will present a diffe...