相同的 MD5 哈希值但使用 hash('md5') 的不同输入

Question

I know that there is some case 2 different strings can have same MD5 hash but when I try with PHP it still become 2 different hash. So is there any string that have same MD5 hash in PHP if I use hash('md5', $blablabla) ?

Answer 1

It is not that simple.

Indeed MD5 is considered as weak today and it is possible to find a collision (another input giving the same hash) under a minute.

Regardless that you have to compute the inputs, just guessing won't work. MD5 produces 128 bit output, so with random guessing will find collision with probability 1/(2^128) (almost impossible)