- Use a new nomenclature for these functions based on the idea of a hash
domain (as in domain separation); this makes much more sence
- Remove the ciphers::hash export; we did not even export a hash
function in the purest sence of the word. This gets us around the
difficulty of figuring out what we should call the underlying
primitive
This finishes the last step of removing sodium.rs from the rosenpass crate
itself and also removes the NOTHING and NONCE0 constants.
Hashing functions now use destination parameters;
rosenpass_constant_time::xor now does too.
