MD5

chicklick

Hi guys.
Antone know how i can decrypt an MD5 hash string?

bonzodog2

Its a kind of one-way process, MD5 hashes are just used to verify the file you downloaded is the same as the one they say it is.

aidan_walsh

MD5 isn't encryption, and isn't intended to be decrypted.

While it can be reverse engineered, thats usually done by creating large tables of many, many possible values and looking up the existing md5 string to see if it matches anything in that and this can take a very long time.

Mike...

What do you want to do with it, There is some freeware about you can use to verify that your download has been uninterrupted or tampered with.

CreepingDeath

aidan_walsh wrote: »

MD5 isn't encryption, and isn't intended to be decrypted.

While it can be reverse engineered, thats usually done by creating large tables of many, many possible values and looking up the existing md5 string to see if it matches anything in that and this can take a very long time.

That's only feasible for very short messages/passwords. In effect you'd be attempting to determine the input string by brute force. if the passwords are weak (simple words in a dictionary) then you can try a dictionary attack, but even dictionary attacks have to be case sensitive for MD5, so "cat" would have 8 variations of spelling with upper and lower characters alone. ( 2 to the power of 3 - letters )

The input string (can be binary) can be any arbitrary length, eg. 4.7Gb DVD image. So you can't really brute force crack it.

Webmonkey

And lets not forget that MD5 hashes don't necessarily have to be unique. You could have two values hash to the same code but the likely hood of this is quite low.

OP, what are you trying to do?

chicklick

Webmonkey wrote: »

And lets not forget that MD5 hashes don't necessarily have to be unique. You could have two values hash to the same code but the likely hood of this is quite low.

OP, what are you trying to do?

I'm trying to fecover a facebook password that i badly need for personal reasons

Webmonkey

Why don't you use the reset password facility?

http://www.facebook.com/reset.php

Or do you mean by "Recover", as in you want to know the password instead of wanting to log into Facebook?

chin_grin

chicklick wrote: »

I'm trying to fecover a facebook password that i badly need for personal reasons

Would you not use the "email new password" facility? If it is your password you're trying to recover?

billymitchell

Sounds like Tom O'Connor is back again looking for help with his hacking
On a serious note, you never mentioned that it is your password that you are trying to reverse engineer, so I am going to ask the question, how have you got only an md5 hash of a facebook password??

As the other said, to retrieve your password, just use the reset password button in Facebook.

Sorry OP/mods if I am sounding off a bit harsh, I just think it seems a bit sus

Webmonkey

Yeah I find the MD5 hash and facebook relationship a bit odd myself.

Chuck Finlay

Please leave your ex-girlfriend alone. She dumped you for a reason, obviously.

chicklick

I'm not a lesbian chuck. sorry guys this is really important and very personal to me but i'm obvioysly going about it the wrong way. but thanks for the effort

Webmonkey

chicklick wrote: »

I'm not a lesbian chuck. sorry guys this is really important and very personal to me but i'm obvioysly going about it the wrong way. but thanks for the effort

I'm just curious to where this MD5 string is coming from that you want to reverse? I certainly doubt you looking inside facebook's users table to find the password.

You have all the answers you want here though

1. MD5 is a one way hash, you can't infer the source from the MD5 hash.
2. You *could* do brute force / dictionary as suggested and hash these and compare. This doesn't not even guarantee however, as the hash's arn't theoretically unique.

billymitchell

chicklick wrote: »

I'm not a lesbian chuck. sorry guys this is really important and very personal to me but i'm obvioysly going about it the wrong way. but thanks for the effort

If you dont want to tell everybody why, pm a mod and give them the reason you want to do this, then maybe they can give us the nod to help you. But I just feel uneasy about helping somebody, what sounds like, hack into somebody else's Facebook account.