ed25519.h File Reference

Ed25519 signatures (RFC 8032) for ssh-ed25519 host keys + client auth. More...

#include "protocore_config.h"

Go to the source code of this file.

Classes
struct	Ed25519Ns
	Dispatch table. Addressed by offset, so the layout is asserted below. More...

Macros
#define	PROTOCORE_ED25519_SEED_LEN   32
	Ed25519 seed (private key) length.
#define	PROTOCORE_ED25519_PUBKEY_LEN   32
	Ed25519 public key length.
#define	PROTOCORE_ED25519_SIG_LEN   64
	Ed25519 signature length (R || S).

Functions
	PROTOCORE_NS_LAYOUT (Ed25519Ns, pubkey, sign, verify)
proto_bool	protocore_ed25519_pubkey (uint8_t *work, const uint8_t *seed, uint8_t *pub)
	Derive the 32-byte public key A from the seed.
proto_bool	protocore_ed25519_sign (uint8_t *work, const uint8_t *seed, const uint8_t *msg, size_t msg_len, uint8_t *sig)
	Sign deterministically (RFC 8032 §5.1.6), writing R || S.
proto_bool	protocore_ed25519_verify (uint8_t *work, const uint8_t *pub, const uint8_t *msg, size_t msg_len, const uint8_t *sig)
	Check a signature (RFC 8032 §5.1.7); the answer is Ed25519Ns::ok.

Variables
PROTOCORE_NS Ed25519Ns Ed25519	PROTOCORE_UNUSED
	Module namespace.

Detailed Description

Ed25519 signatures (RFC 8032) for ssh-ed25519 host keys + client auth.

PureEdDSA over edwards25519. Deterministic signing (RFC 8032 §5.1.6) - no RNG - and verification, built on the shared Curve25519 field arithmetic (protocore_curve25519) and the Sha512Ns entries, so which arm hashes is not visible here. Correctness is pinned to the RFC 8032 §7.1 vectors and to a reference implementation (test_ed25519).

The server signs the KEX exchange hash with its ssh-ed25519 host key, and verifies a client's ed25519 public-key authentication signature.

work is PROTOCORE_ED25519_BORROW secure bytes the CALLER took, at an address it knows. It is not held past the call, so nothing here aliases it. The caller releases it, and the pool wipes on release; this module neither takes it, holds it, releases it, nor wipes it. That is what keeps the expanded seed, the nonce and the challenge from outliving the caller.

Author

Douglas Quigg (dstroy0)

Date

2026

Definition in file ed25519.h.

Macro Definition Documentation

PROTOCORE_ED25519_SEED_LEN

#define PROTOCORE_ED25519_SEED_LEN   32

Ed25519 seed (private key) length.

Definition at line 33 of file ed25519.h.

PROTOCORE_ED25519_PUBKEY_LEN

#define PROTOCORE_ED25519_PUBKEY_LEN   32

Ed25519 public key length.

Definition at line 36 of file ed25519.h.

PROTOCORE_ED25519_SIG_LEN

#define PROTOCORE_ED25519_SIG_LEN   64

Ed25519 signature length (R || S).

Definition at line 39 of file ed25519.h.

Function Documentation

PROTOCORE_NS_LAYOUT()

PROTOCORE_NS_LAYOUT	(	Ed25519Ns	,
		pubkey	,
		sign	,
		verify
	)

protocore_ed25519_pubkey()

proto_bool protocore_ed25519_pubkey	(	uint8_t *	work,
		const uint8_t *	seed,
		uint8_t *	pub
	)

Derive the 32-byte public key A from the seed.

Parameters

work	PROTOCORE_ED25519_BORROW bytes the caller took. Not held past the call.
seed	PROTOCORE_ED25519_SEED_LEN bytes
pub	PROTOCORE_ED25519_PUBKEY_LEN bytes

Returns

PROTO_TRUE on success.

protocore_ed25519_sign()

proto_bool protocore_ed25519_sign	(	uint8_t *	work,
		const uint8_t *	seed,
		const uint8_t *	msg,
		size_t	msg_len,
		uint8_t *	sig
	)

Sign deterministically (RFC 8032 §5.1.6), writing R || S.

Parameters

work	PROTOCORE_ED25519_BORROW bytes the caller took. Not held past the call.
seed	PROTOCORE_ED25519_SEED_LEN bytes
msg	the message
msg_len	its length
sig	PROTOCORE_ED25519_SIG_LEN bytes, R || S

Returns

PROTO_TRUE on success.

protocore_ed25519_verify()

proto_bool protocore_ed25519_verify	(	uint8_t *	work,
		const uint8_t *	pub,
		const uint8_t *	msg,
		size_t	msg_len,
		const uint8_t *	sig
	)

Check a signature (RFC 8032 §5.1.7); the answer is Ed25519Ns::ok.

Parameters

work	PROTOCORE_ED25519_BORROW bytes the caller took. Not held past the call.
pub	PROTOCORE_ED25519_PUBKEY_LEN bytes
msg	the message
msg_len	its length
sig	PROTOCORE_ED25519_SIG_LEN bytes, R || S

Returns

PROTO_TRUE on success.

Variable Documentation

PROTOCORE_UNUSED

PROTOCORE_NS Ed25519Ns Ed25519 PROTOCORE_UNUSED

Initial value:

= {
    .pubkey = protocore_ed25519_pubkey, .sign = protocore_ed25519_sign, .verify = protocore_ed25519_verify}

Module namespace.

Definition at line 81 of file ed25519.h.