Topic: Why do we have to use SHAKE-256 with ed25519 and ed448?
Reading the WolfSSL docs for both the functions wc_ed448ph_sign_hash and wc_ed25519ph_sign_hash, it says that
The hash algorithm used to create message digest must be SHAKE-256
Why is that? I tried signing messages hashed with SHA-512 and SHA3-256 and it seems to work with no errors.
Besides, looking at the ed25519.c file, the implementation for wc_ed25519_sign_msg_ex, which already hashes the message internally, the hash algorithm used is SHA-512, contradicting what the documentation says.