How does one generate a random number in Apple's Swift language?

Question

I realize the Swift book provided an implementation of a random number generator. Is the best practice to copy and paste this implementation in one\'s own program? Or is t

Answer 1

I would like to add to existing answers that the random number generator example in the Swift book is a Linear Congruence Generator (LCG), it is a severely limited one and shouldn't be except for the must trivial examples, where quality of randomness doesn't matter at all. And a LCG should never be used for cryptographic purposes.

arc4random() is much better and can be used for most purposes, but again should not be used for cryptographic purposes.

If you want something that is guaranteed to be cryptographically secure, use SecCopyRandomBytes(). Note that if you build a random number generator into something, someone else might end up (mis)-using it for cryptographic purposes (such as password, key or salt generation), then you should consider using SecCopyRandomBytes() anyway, even if your need doesn't quite require that.