Hash function security summary

Template:Use ymd dates This article summarizes publicly known attacks against cryptographic hash functions. Note that not all entries may be up to date.

Table color key

No known successful attacks

Theoretical break

Attack demonstrated in practice

Common hash functions

Collision resistance

Main article: Collision attack

Hash function	Security claim	Best attack	Attack date	Comment
MD5	264	224.1 time	2007 June	This attack takes seconds on a regular PC.
SHA-1	280	251	2010	No successful reports of this attack yet.
SHA256	2128	24 of 64 rounds (228.5)	2008-11-25
SHA512	2256	24 of 80 rounds (232.5)	2008-11-25

Chosen prefix collision attack

Hash function	Security claim	Best attack	Attack date	Comment
MD5	264	239	2009-06-16	This attack takes hours on a regular PC.
SHA-1	280	263	2006-08-22	Extends Wang's SHA-1 collision attack to partially chosen prefix collisions.
SHA256	2128
SHA512	2256

Preimage resistance

Main article: Preimage attack

Hash function	Security claim	Best attack	Attack date
MD5	2128	2123.4	2009-04-16
SHA-1	2160	45 of 80 rounds	2008-08-17
SHA256	2256	42 of 64 rounds (2251.7)	2008-11-25
SHA512	2512	46 of 80 rounds (2511.5)	2008-11-25

Less common hash functions

Collision resistance

Hash function	Security claim	Best attack	Attack date	Comment
MD2 (cryptography)	264	Template:Nowrap	2009	Slightly less computationally expensive than a birthday attack, but for practical purposes, memory requirements make it more expensive.
MD4	264	3 operations	2007-03-22	Finding collisions almost as fast as verifying them.

Preimage resistance

Hash function	Security claim	Best attack	Attack date
MD2 (cryptography)	2128	273 time, 273 memory	2008
MD4	2128	2102	2008-02-10

See also

• Cryptographic hash function
• Collision attack
• Preimage attack
• Block cipher security summary