Crypt

Hey, I was just trying to encrypt a user inputted password from a form field: $password = crypt($password); I then inserted it into the database, then when a user logs in I am basically comparing the users password encrypted to the one in the database, I have done this before but can't remember if I actually used the crypt function ( might have been md5 ) and for the life of me I can't find the code I wrote. The problem is that when I use the crypt function it keeps creating different encrypted strings from the same password. What am I doing wrong? Regards, Joseph