It really depends on how secure you need your random numbers to be.

If you need a high amount of entropy, don't even think about using rand, or any other PRNG algorithm. There is Crypt::Random, however that depends on Math::Pari which I've had problems installing.

Long story short, if you need security, either use the abovementioned module, or check for the existance of a secure random number device such as /dev/random. Unfortunately, not all operating systems support this device node.