# Problem 78

# Learn about a crypto PRNG

**Due**: April 12

**Points**: 1-2

Look up a PRNG that is considered cryptographically secure, such as Blum-Blum-Shub, Blum-Micali, Yarrow, or Fortuna.

Using **at least two sources** that you document, tell me about the most interesting features of this PRNG, such as:

- Is it actually used in practice? If so, where?
- Is it based on number theory (like RSA type computations) or on block ciphers (such as DES or AES)?
- How does it compare to the non-cryptographic PRNGs we have studied, in terms of speed, period, and state size?

You don't have to write more than one or two sentences to answer each question; I don't need a long essay for this unless you find something really interesting.

**1 point bonus if you learn about a PRNG that no one else picks.**