Function hide_challenge_accept 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn hide_challenge_accept(
    spent: *mut HideSpentNonces,
    challenge: *const u8,
    challenge_len: usize,
    signature: *const u8,
    signature_len: usize,
    public_key: *const u8,
    public_key_len: usize,
    now: u64,
) -> i32

Accepts a challenge answer exactly once. A valid signature replayed a second time returns HIDE_ERR_CHALLENGE_REPLAYED, which is the entire reason this call takes a spent record rather than being a pure function.

Safety

All pointers must be valid for the stated lengths.