[Marc De Joya]

How can I decrypt a variable once it has been encryted in sha1 or md5?

[Coksnuss]

SHA1 and MD5 are hash algorithms, i.e. they do not encrypt your value. One of the goals of hashing algorithms is to give you a hard time to reverse them.
Decrypting is only possible with a dictonary attack or by bruteforce.

[Tropi]

 Coksnuss, on 17 April 2013 - 03:01 PM, said:

Decrypting is only possible with a dictonary attack or by bruteforce.

This is not true. Hashes are non-reversable. This is also true for weak hashing algorithms, the problem with those is, that you don't actually have to find the original plain text, any collision will do.


@topic: You could also use rainbow tables. But as already said, you can't decrypt a hash.

[Da:Sourcerer]

Toss the hashes into Google. md5 and sha1 are widespread hash methods, so if the hashed value is common, chances are good something comes up.

[samdark]

Hashes are irreversable but with modern hardware you can bruteforce even sha256 very fast.