Derive a key pair from an optional secret seed.

As in RFC 8032, an Ed25519 public key is generated by hashing the secret key using the SHA-512 function, and interpreting the bit-swapped, clamped lower-half of the output as the secret scalar.

For this reason, an EdDSA secret key is commonly called a seed, from which the actual secret is derived.

Parameters

seed: ?[seed_length]u8,