SHA-1

1 Specification

• digest size: 160 bits
• max. message length: < 2⁶⁴ bits
• 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 et al. It has complexity of 2⁶⁹ hash evaluations. The best collision example, a 70-step collision for SHA-1, was published by DeCanniere, Mendel and Rechberger.

---

2.2 Collision Attacks

Christophe De Canni\`ere, Christian Rechberger - Finding SHA-1 Characteristics: General Results and Applications

ASIACRYPT 4284:1-20,2006

http://dx.doi.org/10.1007/11935230_1
Bibtex

Author : Christophe De Canni\`ere, Christian Rechberger
Title : Finding SHA-1 Characteristics: General Results and Applications
In : ASIACRYPT -
Address :
Date : 2006

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

Selected Areas in Cryptography 3897:261-275,2005

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 : Selected Areas in Cryptography -
Address :
Date : 2005

Vincent Rijmen, Elisabeth Oswald - Update on SHA-1

CT-RSA pp. 58-71,2005

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

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

---

2.3 Preimage Attacks

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

---

2.4 Others

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

ISC 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 -
Address :
Date : 2005

3 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.