SHA-1

1 General

• digest size: 160 bits
• max. message length: < 2⁶⁴ bits
• type: iterative hash function
• compression function: 512-bit message block, 160-bit chaining variable
• Specification: FIPS 180-2 Secure Hash Standard

2 Cryptanalysis

2.1 Best Known Results

The best collision attack on full SHA-1 was published by Wang etal. It has complexity of 2⁶⁹ hash evaluations. The best collision example, a 64-step collision for SHA-1, was publshed by DeCanniere and Rechberger.

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2.2 Collision Attacks

Michael Szydlo, Yiqun Lisa Yin - Collision-Resistant Usage of MD5 and SHA-1 Via Message Preprocessing.

CT-RSA 2006 3860:99-114,2006

http://dx.doi.org/10.1007/11605805_7
Bibtex

Author : Michael Szydlo, Yiqun Lisa Yin
Title : Collision-Resistant Usage of MD5 and SHA-1 Via Message Preprocessing.
In : CT-RSA 2006 -
Address :
Date : 2006

Norbert Pramstaller, Christian Rechberger, Vincent Rijmen - Exploiting Coding Theory for Collision Attacks on SHA-1

Cryptography and Coding 2005 3796:78-95,2005

http://dx.doi.org/10.1007/11586821_7
Bibtex

Author : Norbert Pramstaller, Christian Rechberger, Vincent Rijmen
Title : Exploiting Coding Theory for Collision Attacks on SHA-1
In : Cryptography and Coding 2005 -
Address :
Date : 2005

Norbert Pramstaller, Christian Rechberger, Vincent Rijmen - Impact of Rotations in SHA-1 and Related Hash Functions.

SAC 2005 3897:261-275,2006

http://dx.doi.org/10.1007/11693383_18
Bibtex

Author : Norbert Pramstaller, Christian Rechberger, Vincent Rijmen
Title : Impact of Rotations in SHA-1 and Related Hash Functions.
In : SAC 2005 -
Address :
Date : 2006

Xiaoyun Wang, Andrew Yao, Frances Yao - New Collision Search for SHA-1

, August 2005

Bibtex

Author : Xiaoyun Wang, Andrew Yao, Frances Yao
Title : New Collision Search for SHA-1
In : -
Address :
Date : August 2005

Xiaoyun Wang, Andrew Yao, Frances Yao - Cryptanalysis of SHA-1

, October 2005

Bibtex

Author : Xiaoyun Wang, Andrew Yao, Frances Yao
Title : Cryptanalysis of SHA-1
In : -
Address :
Date : October 2005

Xiaoyun Wang, Yiqun Lisa Yin, Hongbo Yu - Finding Collisions in the Full SHA-1

Advances in Cryptology - CRYPTO 2005 3621:17--36,2005

http://dx.doi.org/10.1007/11535218_2
Bibtex

Author : Xiaoyun Wang, Yiqun Lisa Yin, Hongbo Yu
Title : Finding Collisions in the Full SHA-1
In : Advances in Cryptology - CRYPTO 2005 -
Address :
Date : 2005

Vincent Rijmen, Elisabeth Oswald - Update on SHA-1

CT-RSA 2005 3376:58--71,2005

http://dx.doi.org/10.1007/b105222
Bibtex

Author : Vincent Rijmen, Elisabeth Oswald
Title : Update on SHA-1
In : CT-RSA 2005 -
Address :
Date : 2005

Eli Biham, Rafi Chen, Antoine hirose, Patrick Carribault, Christophe Lemuet, William Jalby - Collisions of SHA-0 and Reduced SHA-1

Advances in Cryptology - EUROCRYPT 2005 3494:36--57,2005

http://dx.doi.org/10.1007/11426639_3
Bibtex

Author : Eli Biham, Rafi Chen, Antoine hirose, Patrick Carribault, Christophe Lemuet, William Jalby
Title : Collisions of SHA-0 and Reduced SHA-1
In : Advances in Cryptology - EUROCRYPT 2005 -
Address :
Date : 2005

Akashi Satoh - Hardware Architecture and Cost Estimates for Breaking SHA-1.

ISC 2005 3650:259-273,2005

http://dx.doi.org/10.1007/11556992_19
Bibtex

Author : Akashi Satoh
Title : Hardware Architecture and Cost Estimates for Breaking SHA-1.
In : ISC 2005 -
Address :
Date : 2005

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2.3 Second Preimage Attacks

John Kelsey, Bruce Schneier - Second Preimages on n-Bit Hash Functions for Much Less than 2ⁿ Work.

EUROCRYPT 3494:474-490,2005

http://dx.doi.org/10.1007/11426639_28
Bibtex

Author : John Kelsey, Bruce Schneier
Title : Second Preimages on n-Bit Hash Functions for Much Less than 2ⁿ Work.
In : EUROCRYPT -
Address :
Date : 2005

Note: This artcle shows that second preimages can be found in much less than 2ⁿ work. This approach works for all iterated hash functions. Nevertheless, this attack is not practical since a inpractical amount of data is required.

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2.4 Preimage Attacks

• We are not aware of any articles w.r.t. preimage attacks on SHA-1.

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2.5 Others

Markku-Juhani Olavi Saarinen - Cryptanalysis of Block Ciphers Based on SHA-1 and MD5.

FSE 2003 2887:36-44,2003

http://springerlink.metapress.com/content/xu0qg98tg38gl7nf/?p=2664f1c23d3f433f9d3fd6a9a1350eda&pi=3
Bibtex

Author : Markku-Juhani Olavi Saarinen
Title : Cryptanalysis of Block Ciphers Based on SHA-1 and MD5.
In : FSE 2003 -
Address :
Date : 2003

Helena Handschuh, Lars R. Knudsen, Matthew J. B. Robshaw - Analysis of SHA-1 in Encryption Mode.

CT-RSA 2001 2020:70-83,2001

http://link.springer.de/link/service/series/0558/bibs/2020/20200070.htm
Bibtex

Author : Helena Handschuh, Lars R. Knudsen, Matthew J. B. Robshaw
Title : Analysis of SHA-1 in Encryption Mode.
In : CT-RSA 2001 -
Address :
Date : 2001

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3 Performance Evaluation / Implementation (HW and SW)

Yong Ki Lee, Herwin Chan, Ingrid Verbauwhede - Throughput Optimized SHA-1 Architecture Using Unfolding Transformation.

ASAP 2006 pp. 354-359,2006

http://doi.ieeecomputersociety.org/10.1109/ASAP.2006.68
Bibtex

Author : Yong Ki Lee, Herwin Chan, Ingrid Verbauwhede
Title : Throughput Optimized SHA-1 Architecture Using Unfolding Transformation.
In : ASAP 2006 -
Address :
Date : 2006

4 eHash Recommendation (optional) or eHash Opinion

Something like: SHA-1 is considered to be broken. Please do not incorporate SHA-1 in new application any longer. Try to migrate to another hash function.