Re:Announcing the first SHA-1 collision
by glitch003 on Thursday February 23, 2017 @11:02PM
(#13720879)
Yes, this is correct. It's a really simple principle, and I think an explanation can help you understand :)
Suppose you have 3 holes, and 4 pigeons, and you stuff the pigeons into holes. There must be 1 hole with at least 2 pigeons, right?
The same is true with hash functions. If you're hashing data down to a fixed length, like say 256-bits with sha-256, and the data is longer than 256 bits, there must be a collision somewhere.
Suppose you have 3 holes, and 4 pigeons, and you stuff the pigeons into holes. There must be 1 hole with at least 2 pigeons, right?
The same is true with hash functions. If you're hashing data down to a fixed length, like say 256-bits with sha-256, and the data is longer than 256 bits, there must be a collision somewhere.