NIST Defines New Versions of SHA-512
NIST has just defined two new versions of SHA-512. They’re SHA-512/224 and SHA-512/256: 224- and 256-bit truncations of SHA-512 with a new IV. They’ve done this because SHA-512 is faster than SHA-256 on 64-bit CPUs, so these new SHA variants will be faster.
This is a good thing, and exactly what we did in the design of Skein. We defined different outputs for the same state size, because it makes sense to decouple the internal workings of the hash function from the output size.