Collision attack
Cryptographic attack / From Wikipedia, the free encyclopedia
In cryptography, a collision attack on a cryptographic hash tries to find two inputs producing the same hash value, i.e. a hash collision. This is in contrast to a preimage attack where a specific target hash value is specified.
This article provides insufficient context for those unfamiliar with the subject. (February 2020) |
There are roughly two types of collision attacks:
- Classical collision attack
- Find two different messages m1 and m2 such that hash(m1) = hash(m2).
More generally:
- Chosen-prefix collision attack
- Given two different prefixes p1 and p2, find two suffixes s1 and s2 such that hash(p1 ∥ s1) = hash(p2 ∥ s2), where ∥ denotes the concatenation operation.