SHA-256/224

1 Specification

• digest size: 256 bits
• max. message length: < 2⁶⁴ bits
• compression function: 512-bit message block, 256-bit chaining variable
• Specification: FIPS 180-2 Secure Hash Standard

2 Cryptanalysis

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2.2 Generic Attacks

• Generic Attacks on the Merkle-Damgaard Construction

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2.3 Collision Attacks

</bibtex> @inproceedings{sacryptYoshidaB05,

 author    = {Hirotaka Yoshida and Alex Biryukov},
 title     = {Analysis of a SHA-256 Variant},
 booktitle = {Selected Areas in Cryptography},
 year      = {2005},
 pages     = {245-260},
 url        = {http://dx.doi.org/10.1007/11693383_17},
 editor    = {Bart Preneel and Stafford E. Tavares},
 publisher = {Springer},
 series    = {LNCS},
 volume    = {3897},
 isbn      = {3-540-33108-5},
 abstract  = {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 differential attack on these constructions by using one-round iterative differential characteristics with probability 2^{-8} we identified. Our result shows that SHACAL-2-XOR with up to 31 rounds out of 64 has a weakness of randomness and that SHA-2-XOR with up to 34 rounds has a weakness of pseudo-collision resistance. Using the 31-round distinguisher, we present an attack on SHACAL-2-XOR with up to 32 rounds. We also show that no 2-round iterative patterns with probability higher than 2^{-16} exist.},

} </bibtex>

Hirotaka Yoshida, Alex Biryukov - Analysis of a SHA-256 Variant

Selected Areas in Cryptography 3897:245-260,2005

http://dx.doi.org/10.1007/11693383_17
Bibtex

Author : Hirotaka Yoshida, Alex Biryukov
Title : Analysis of a SHA-256 Variant
In : Selected Areas in Cryptography -
Address :
Date : 2005

Henri Gilbert, Helena Handschuh - Security Analysis of SHA-256 and Sisters

Selected Areas in Cryptography 3006:175-193,2003

http://springerlink.metapress.com/openurl.asp?genre=article{\&}issn=0302-9743{\&}volume=3006{\&}spage=175
Bibtex

Author : Henri Gilbert, Helena Handschuh
Title : Security Analysis of SHA-256 and Sisters
In : Selected Areas in Cryptography -
Address :
Date : 2003

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