Provide the possibility to add a salt when calculating and verifiying the MD5 hash of a password

Richard,

Does the salt need to be protected? Would it be sufficient to have a setSalt method on the realm and related credential methods?

If the configuration file that contains the salt is compromised at the same time as the stored MD5 hashes, is there any additional protection?

Sorry if this is a dumb question, but I don't want to appear to be adding extra security unless I get it 100% correct.

Greg,

please refer to http://en.wikipedia.org/wiki/Salting_(cryptography), I am afraid that I cannot account as deep expert, to be honest.

Anyways, from my knowledge,the salt should not be per realm but rather per user. Therefore as a first step I would recommend the possibility to add a salt provider to the realm. Whenever the hash is calculated the salt provider is asked for the salt (returning a byte array), with the user name as parameter. Implementations would than have the possibility to inject the salt stored along with the user. The default implementation may store the user specific salt along with the hashed password, making the leaked hashes more secure against rainbow table attacks http://en.wikipedia.org/wiki/Rainbow_tables. Even though the salt is leaked with the hash in that case, it requires computing a rainbow table for each user which then is effectively the same as a brute force attack (rainbow tables for plain passwords can be downloaded from the internet), making the attack infeasible for strong passwords.

While we are at it : MD5 has severe vulnerabilities, see http://en.wikipedia.org/wiki/MD5#Security, you might consider offering AES support as well or open up the Credential class in a way that a client may choose his favourite hashing algorithm (this would also enable support for the currently planned successor of AES). But this may be worth a separate bug report.

Regards
Richard

Edit: Also a great read on the topic: http://chargen.matasano.com/chargen/2007/9/7/enough-with-the-rainbow-tables-what-you-need-to-know-about-s.html

Jesse,

can you take this to best of breed status.

Richard,
thanks for the information and pointers.

Salt is a must with hashed password. Otherwise MD5 passwords are extremely insecure. Current functionality is unusable. (JDBCLoginModule is also unusable)

Please?