Why is MD5'ing a UUID not a good idea?

Question

PHP has a uniqid() function which generates a UUID of sorts.

In the usage examples, it shows the following:

$token = md5(uniqid());

But in t

Answer 1

As an aside, MD5 is actually obsolete and is not to be used in anything worth protecting - PHI, PII or PCI - from 2010 onwards. The US Feds have ennforced this and any entity non-compliant would be paying lots of $$$ in penalty.