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    No, there is no way to decrypt MD5, because MD5 is not a cipher. But as you probably meant its reversibility, you can only remember input+output pairs for a later lookup or try to find collisions. But you cannot ‘decrypt’ it. Commented Mar 4, 2013 at 4:59
  • @Gumbo: how do the MD5 decryptors work? It doesn't matter whether they store the key value strings, the process suggests that MD5 doen't use a custom salt which means it can be reversed if you get to the core of it. Commented Jun 14, 2013 at 4:52
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    Here's an oversimplified way of putting it: 5+5 is 10, but if you just have 10 you can't know that the original numbers were 5 and 5. However, if you know the algorithm (take two numbers and add them), then you can reverse the 10 to get 3+7 and it will be accepted because the result is the same. Commented Jun 14, 2013 at 4:55
  • @Fr0zenFyr They are just huge lookup tables: Any known hash is mapped onto the input that was used to generate it; if someone looks up a hash that is known, you’ll get the input value. Commented Jun 14, 2013 at 5:21
  • @Kolink It’s not that easy. Cryptographic hash functions should have the property that it’s infeasible to generate an input that has a given hash (pre-image attack). Commented Jun 14, 2013 at 5:22