SHA-2 is also length-extendable, which means you have to be careful when you use it to build a MAC. (That's why I like the truncated version).
No cryptographer I know takes these particular "what-if's" seriously. They appear to come exclusively from non-cryptographers reacting to anything that NIST touched.
No cryptographer I know takes these particular "what-if's" seriously. They appear to come exclusively from non-cryptographers reacting to anything that NIST touched.