Take the 2-minute tour ×
Information Security Stack Exchange is a question and answer site for Information security professionals. It's 100% free, no registration required.

This question already has an answer here:

I use bcrypt (32 rounds) and once the hash is produced, I get the sha512 of that hash and I then hash that with blow fish and once that is done, I hash it again with sha512 with a salt that has been hashed with bcrypt (94 rounds) that is 33 characters long to each user password.

So is that secure or not?

share|improve this question

marked as duplicate by Adnan, TildalWave, Xander, Lucas Kauffman, Terry Chia Mar 12 at 15:11

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

2 Answers 2

Yes but everything after the first bcrypt is completely unnecessary. bcrypt automatically generates and appends a salt as well (in the ruby implementation anyway), and changing the number of rounds is sufficient to ensure that the hashing scheme is slow enough to deter offline brute forcing.

share|improve this answer

Your scheme is as secure as bcrypt with 32 rounds, but much more complicated. Adding complexity does not increase the security of the system, it just makes it more likely to have bugs.

The SHA-512 and Blowfish-based hashes don't add any significant work factor compared to the bcrypt. And the extra rounds of bcrypt applied to the salt add nothing to the difficulty of brute-force password guessing, because it only needs to be calculated once per target password, not once per guess.

I would strongly suggest just using standard bcrypt. To increase the hash strength just increase the number of rounds. (A lot - assuming you mean 32 iterations, that's next to nothing. See Recommended # of rounds for bcrypt for more realistic numbers.)

This will aid interoperability and allow you to increase the number of rounds as you go forward without breaking all your existing hashes.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.