How exactly does MD5 work? What is it?

[eac]

Hello, I do visit the manual. However, is there an english based simple answer that can help me truely grasp how it works and why I would want to use it? A non technical way to help me see how I would start to use it and how it benefits me as a programmer.

Thanks

[jofa]

http://www.ietf.org/rfc/rfc1321.txt

The simple answer: a one-way function is useful if you want to compare two values, x and y, without sending the value x to the location where y is or v.v.
E.g. if md5(password_from_client) == md5(password_in_database), then password_from_client == password_in_database (and the value you send from the client to the server is of course md5(password_from_client), not the password

"Guessing" the correct 128 bit number will take a few billion years or so (I think)

[eac]

""Guessing" the correct 128 bit number will take a few billion years or so (I think)"

And I don't have a php script to lenghten my life by that total, so in essence, that would be a bad thing.

Seriously, thanks for the tip

[raincrow]

Originally posted by eac
""Guessing" the correct 128 bit number will take a few billion years or so (I think)"

And I don't have a php script to lenghten my life by that total, so in essence, that would be a bad thing.

Actually, it is a good thing. If, somehow, your list of MD5-hashed passwords was compromised, it would be EXTREMELY unlikely to yield any useful information except via brute-force methods, which, as already established would take quite a while.

MSM