pub fn prefix_cv(master: &[u8; 32], signer: &[u8; 32]) -> [u32; 8]Expand description
Host-side: chaining value after hashing master ‖ signer as key material.
The key material is master (32 B) ‖ signer identity (32 B) ‖ epoch ‖ batch ‖ index. Its first 64 bytes are the same for every key of a run,
so the host compresses them once here; the FPGA continues from this
value with seed_request.