Using UUIDs does not magically solve your problem of using a bad PRNG. RFC 4122 imposes no guarantees on how random the V4 UUIDs really are. You'll still need t

Using UUIDs does not magically solve your problem of using a bad PRNG. RFC 4122 imposes no guarantees on how random the V4 UUIDs really are. You'll still need to verify yourself if the method you use to generate them is good enough for your application. Especially if you need your UUIDs to be unpredictable. It even says so explicitly: Do not assume that UUIDs are hard to guess; they should not be used as security capabilities (identifiers whose mere possession grants access), for example. A predictable random number source will exacerbate the situation. So many people use UUIDs for session cookies, where the unpredictability is vital.