Niels Möller writes:
With support for SHA3, it seems clear that nettle's naming for sha2 functions was a mistake. It should be "sha2_256", rather than "sha256".
While such a step would be logical, I'd like to note that while SHA-2 algorithms are widely known as SHA-256, etc., it's the SHA3-256, etc. forms that seems to be preferred for SHA-3.
There's a logic in keeping the things as they are, too. When SHA-1 was introduced, it supported only 160 bit size digests, so there was no need to mention the size explicitly. When SHA-2 appeared, it supported several sizes, but none of them coincided with the SHA-1's 160 bits, thus the “version” was apparent from the bit size. At last, came SHA-3, and being the later one, it has to bear its explicit version number.
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