Function small_order_encoding 

pub fn small_order_encoding(bytes: &[u8; 32]) -> bool

The eight encodings of low-order points that strict verification rejects (the list rhdl_ed25519_fast_core checks).

These are the canonical encodings of the eight points of the torsion subgroup (order dividing 8), compared as four little-endian 64-bit words. With a small-order key, [k]A takes at most eight values, so a signature can be forged without the secret key; strict verifiers refuse these encodings.