/*
 * Copyright (C) 2023 - 2026, Stephan Mueller <smueller@chronox.de>
 *
 * License: see LICENSE file in root directory
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

#ifndef LC_ED25519_H
#define LC_ED25519_H

#include "lc_rng.h"
#include "lc_status.h"

#ifdef __cplusplus
extern "C" {
#endif

#define LC_ED25519_RAW_SECRETKEYBYTES (32U)
#define LC_ED25519_PUBLICKEYBYTES (32U)
#define LC_ED25519_SECRETKEYBYTES                                              \
	(LC_ED25519_RAW_SECRETKEYBYTES + LC_ED25519_PUBLICKEYBYTES)
#define LC_ED25519_SIGBYTES (64U)

struct lc_ed25519_sk {
	uint8_t sk[LC_ED25519_SECRETKEYBYTES];
};

struct lc_ed25519_pk {
	uint8_t pk[LC_ED25519_PUBLICKEYBYTES];
};

struct lc_ed25519_sig {
	uint8_t sig[LC_ED25519_SIGBYTES];
};

int lc_ed25519_keypair(struct lc_ed25519_pk *pk, struct lc_ed25519_sk *sk,
		       struct lc_rng_ctx *rng_ctx);
int lc_ed25519_pk_from_sk(struct lc_ed25519_pk *pk,
			  const struct lc_ed25519_sk *sk);
int lc_ed25519_derive_pk(struct lc_ed25519_pk *pk, struct lc_ed25519_sk *sk);
int lc_ed25519_sign(struct lc_ed25519_sig *sig, const uint8_t *msg, size_t mlen,
		    const struct lc_ed25519_sk *sk, struct lc_rng_ctx *rng_ctx);
int lc_ed25519_verify(const struct lc_ed25519_sig *sig, const uint8_t *msg,
		      size_t mlen, const struct lc_ed25519_pk *pk);

/* Receive a message pre-hashed with SHA-512 */
int lc_ed25519ph_sign(struct lc_ed25519_sig *sig, const uint8_t *msg,
		      size_t mlen, const struct lc_ed25519_sk *sk,
		      struct lc_rng_ctx *rng_ctx);
int lc_ed25519ph_verify(const struct lc_ed25519_sig *sig, const uint8_t *msg,
			size_t mlen, const struct lc_ed25519_pk *pk);

enum lc_ed25519_alg_operation {
	/** Unknown operation */
	lc_alg_operation_ed25519_unknown,
	/** ED25519: key generation operation */
	lc_alg_operation_ed25519_keygen,
	/** ED25519: signature generation operation */
	lc_alg_operation_ed25519_siggen,
	/** ED25519: signature verification operation */
	lc_alg_operation_ed25519_sigver,
};

/**
 * @brief Obtain algorithm status
 *
 * @param [in] operation ED25519 algorithm type
 *
 * @return algorithm status
 */
enum lc_alg_status_val
lc_ed25519_alg_status(const enum lc_ed25519_alg_operation operation);

#ifdef __cplusplus
}
#endif

#endif /* LC_ED25519_H */
