Pseudo-random Number generation for Passwords I am looking for a good pseudo-random number generation algorithm for passwords. 

My scenario is that I have to generate 5K pseudo-random bits from a user-supplied password (6 characters). What are possible options and which one would be able to cover for my purposes?
Scrypt is the best function for key-stretching we have. With such a bad password, you'll need all the stretching you can get, so make sure to use a large work parameter and a fast implementation.

But you should really consider using a stronger password. 10 random characters are much better than only 6.