[fpc-pascal] quality of FPC random

[Jonas Maebe]

Xiangrong Fang wrote on Fri, 14 Aug 2015:

> I need to generate random numbers to be used as IV of block ciphers.  My
> question is: is FPC built-in PRNG good enough as comparing to /dev/urandom?

No PRNG is suited for that purpose, because every PRNG is by  
definition predictable and you need unpredictable numbers for IVs.

> On the other hand, /dev/urandom in my impression is fairly slow, how is the
> speed of Random() comparing to that?

They are not comparable, they serve completely different purposes.  
Additionally, the speed of /dev/urandom depends on a lot of factors  
(it gets its input from various kinds of activity on the system, so  
the more activity there is, the faster it becomes).


Jonas