How can it be impossible to "decrypt" an MD5 hash?

Posted by Rob on Stack Overflow See other posts from Stack Overflow or by Rob
Published on 2010-04-27T00:27:58Z Indexed on 2010/04/27 0:33 UTC
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md5

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hash

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decryption

I was reading a question about MD5, and it made me remember something that boggles me. Very simple question, and I'm sorry if it's not a good one. I just can't understand how you convert something to one thing using some algorithm, and there being no way to convert it back using the algorithm in reverse.

So how is this possible?

Also, since multiple strings can create the same MD5 hash, due to it being less data than the input string, how would any other hashing system be any better?

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