> It is only missing key stretching with fast cryptographic hashing algorithms like SHA-1 or SHA-2. Instead, it jumps right into PBKDF2 and bcrypt. Key stretch

> It is only missing key stretching with fast cryptographic hashing algorithms like SHA-1 or SHA-2. Instead, it jumps right into PBKDF2 and bcrypt. Key stretching with SHA-1 or SHA-2 is hard to do right, and if you do it right, you've reached a solution that is basically equivalent to PBKDF2 or bcrypt. If you're interested in how PBKDF2 or bcrypt are implemented, that's one thing, but if you're rolling your own password stretching on top of SHA-1 or SHA-2, you're probably not doing it correctly and performing [security theater](http://en.wikipedia.org/wiki/Security_theater http://en.wikipedia.org/wiki/Security_theater). > PBKDF2 and bcrypt can be a performance killer for authentication applications, if the host is a busy host. Instead, changing the number of rotations on a fast hashing algorithm gives you finer granularity on brute force speed versus application and host reliability. This is already provided by PBKDF2 and bcrypt. Both can be configured to run more or fewer rounds.