/* ed25519.h -- EdDSA signature VERIFICATION only (RFC 8032), freestanding
 * C99. No signing, no key generation, no RNG -- this kernel never signs;
 * signing happens in the host-side build tool, which can link
 * libsodium/OpenSSL because it's a normal Linux binary. That halves the
 * implementation surface here: no scalar clamping, no key derivation, no
 * constant-time discipline (verify operates only on public data --
 * public key, message, signature -- there's no secret-dependent branch
 * to leak).
 */
#ifndef ED25519_H
#define ED25519_H

#include <stdint.h>
#include <stddef.h>

/* Returns 1 if signature (64 bytes: R || S) is a valid Ed25519 signature
 * by pubkey (32 bytes, compressed point) over msg, else 0. Rejects
 * malformed inputs (S >= L, an undecodable point) as invalid rather than
 * faulting. */
int ed25519_verify(const uint8_t pubkey[32], const uint8_t *msg, size_t msg_len,
                    const uint8_t sig[64]);

#endif /* ED25519_H */