On Jan 19, 2008 8:02 PM, Jochem Maas <jochem@xxxxxxxxxxxxx> wrote: > Nathan Nobbe schreef: > > hi all, > > > > recently ive been debating a bit about the use of the crypt() function and > > the best practice thereof, im hoping you can help to clarify this for me. > > > > so, the crypt function > > http://www.php.net/manual/en/function.crypt.php > > has a second parameter, $salt, which, if not supplied will be automatically > > generated and presumably become a prefix or suffix of the returned string. > > > > now, the article on the phpsec website > > http://phpsec.org/articles/2005/password-hashing.html > > recommends to externally create a salt and to store that in a separate field > > in the database, which would then be used for subsequent password > > verification. > > > > theoretically, however, if the password is generated without a user supplied > > salt, > > there is a salt already embedded in the password anyway. > > > > so, i have the following questions > > > > 1. is the phpsec technique bloated or unnecessary > > I can't see a dictionary attack being thwarted by the salt given that the salt > is made available when a password is checked. I'm struggling to see how a salt > will help if it's made available. but it's late, may be better brain can enlighten us :-) > > then again your question is a little skewed due to the fact that sha1() is > used in the phpsec article and your talking about crypt - which encryption is > better as it stands is the first question to ask no? AFAIK sha1() is > recommended over DES but maybe I'm misinformed. > > > 2. is it better to create a user supplied salt, and why or why not > > 3. is crypt() 'intended' to be used w/o a user provided salt, since it > > is a stable algorithm > > depends on the use - i.e. using it inconjunction with a .htpasswd file > will required no salt (auto-generated salt), other usage recommends using > an explicit salt. > > all this salt is hurting my eyes - I have a blind spot. > > > > > > any other direction or hints you can supply are much appreciated. > > > > thanks, > > > > -nathan > > > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > > They say sha1 has been compromised. http://en.wikipedia.org/wiki/SHA_hash_functions I always make sure that I use a site specific salt which is just appended on the user supplied value. I started doing that when I read that people had created huge databases of hashed values that they can just search on. At least this way no matter what the password isn't a dictionary word. As for if that really adds value in the end I can't say as I'm not really a security expert. Eg. hash('sha256', $input.$salt); -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
