-3

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)?

Maarten Bodewes
  • 90,524
  • 13
  • 150
  • 263
DŨNG ĐỖ
  • 11
  • 2
  • 1
    Do you have an actual programming question? Otherwise https://en.wikipedia.org/wiki/MD5#Collision_vulnerabilities – Jonnix Mar 20 '19 at 17:13
  • Possible duplicate of [Can two different strings generate the same MD5 hash code?](https://stackoverflow.com/questions/1756004/can-two-different-strings-generate-the-same-md5-hash-code) – Abdur Rehman Mar 20 '19 at 17:21
  • In terms of security this might interest you as well: https://www.whitehatsec.com/blog/magic-hashes/ It shows how some hashes can be bypassed when you aren't using a strict comparison in php. – SerAlejo Mar 20 '19 at 20:16

1 Answers1

0

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)

gusto2
  • 11,210
  • 2
  • 17
  • 36