Hacker News Reader

Is anyone familiar with the Secure Remote Password protocol, and how secure it is in comparison to hashing and salting passwords using algorithms like bcrypt and PBKDF2?

View on HN

SRP is a protocol to authenticate without exchanging passwords. It has the advantage that the server only ever sees and stores a verifier based on the hashed password. However, the password is still vulnerable to brute forcing. There is an extra modulo exponentiation which may make GPU calculation harder. I think the default hash for the verifier is SHA-1. It is possible to use a slow hash, like PBKDF2, for the verifier.

It is also, unfortunately, infeasible to use in web applications without some kind of plugin, much less across many different browsers. Blizzard still needs people to be able to log into battle.net to renew their subscriptions and buy vanity mounts.

If you control the client side and it's a normal client/server-type application, absolutely, go for it. It poses much less risk to your users than any scrambling or key derivation protocol, no matter how strong. (Those do nothing to prevent getting your favorite password by snooping on ethernet traffic or memory, for example.) As you mentioned, SRP too has adjustable knobs.

Reply on news.ycombinator.com