Jarod Posted November 15, 2009 Share Posted November 15, 2009 like if I inputted Jays, which is 3bc7b0fecbd8e586fcdaf70feaeaab9e in MD5, how do I reverse 3bc7b0fecbd8e586fcdaf70feaeaab9e so that it outputs Jays though? Quote Link to comment https://forums.phpfreaks.com/topic/181582-is-there-a-way-to-like-unset-the-md5/ Share on other sites More sharing options...
Alex Posted November 15, 2009 Share Posted November 15, 2009 MD5 cannot be reversed, that's the point. Quote Link to comment https://forums.phpfreaks.com/topic/181582-is-there-a-way-to-like-unset-the-md5/#findComment-957779 Share on other sites More sharing options...
Jarod Posted November 15, 2009 Author Share Posted November 15, 2009 I guess, I was just curious though :'(. Quote Link to comment https://forums.phpfreaks.com/topic/181582-is-there-a-way-to-like-unset-the-md5/#findComment-957783 Share on other sites More sharing options...
joel24 Posted November 15, 2009 Share Posted November 15, 2009 not exactly sure what you wanted it for, but you can encrypt/decrypt AES/DES encryptions with mysql... http://dev.mysql.com/doc/refman/5.1/en/encryption-functions.html Quote Link to comment https://forums.phpfreaks.com/topic/181582-is-there-a-way-to-like-unset-the-md5/#findComment-957786 Share on other sites More sharing options...
phpSensei Posted November 15, 2009 Share Posted November 15, 2009 Simple things like Jay or other strings that are md5 hashed can be reversed using brute force, which I won't go into details with. This is why having a combination of numbers and/or numbers with capitals and such can make it difficult for someone to decrypt passwords and such. Quote Link to comment https://forums.phpfreaks.com/topic/181582-is-there-a-way-to-like-unset-the-md5/#findComment-957802 Share on other sites More sharing options...
RichardRotterdam Posted November 15, 2009 Share Posted November 15, 2009 I suggest looking up what the difference is between Hash and encryption. Also lookup what rainbow tables are and why people add "salt" to passwords. Looking those definitions up should inform you enough. Quote Link to comment https://forums.phpfreaks.com/topic/181582-is-there-a-way-to-like-unset-the-md5/#findComment-957870 Share on other sites More sharing options...
Daniel0 Posted November 15, 2009 Share Posted November 15, 2009 Hashing functions do not have an inverse because they're not bijections. It should be quite obvious why for instance MD5 isn't invertible. Its output is always 32-bit, so if you give it 33-bit input (or n-bit input for n > 32) you've lost information. How would you figure out what the last bit(s) should be? Please not that you cannot "reverse" it by brute-force either. You can find input that has the same hash though. Kind of like n^2 = (-n)^2 but -n != n where n is a positive real number. Quote Link to comment https://forums.phpfreaks.com/topic/181582-is-there-a-way-to-like-unset-the-md5/#findComment-957885 Share on other sites More sharing options...
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