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/*
* Interface of curve P-256 (ECDH and ECDSA)
*
* Copyright The Mbed TLS Contributors
* Author: Manuel Pégourié-Gonnard.
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#ifndef P256_M_H
#define P256_M_H
#include <stdint.h>
#include <stddef.h>
/* Status codes */
#define P256_SUCCESS 0
#define P256_RANDOM_FAILED -1
#define P256_INVALID_PUBKEY -2
#define P256_INVALID_PRIVKEY -3
#define P256_INVALID_SIGNATURE -4
#ifdef __cplusplus
extern "C" {
#endif
/*
* RNG function - must be provided externally and be cryptographically secure.
*
* in: output - must point to a writable buffer of at least output_size bytes.
* output_size - the number of random bytes to write to output.
* out: output is filled with output_size random bytes.
* return 0 on success, non-zero on errors.
*/
extern int p256_generate_random(uint8_t * output, unsigned output_size);
/*
* ECDH/ECDSA generate key pair
*
* [in] draws from p256_generate_random()
* [out] priv: on success, holds the private key, as a big-endian integer
* [out] pub: on success, holds the public key, as two big-endian integers
*
* return: P256_SUCCESS on success
* P256_RANDOM_FAILED on failure
*/
int p256_gen_keypair(uint8_t priv[32], uint8_t pub[64]);
/*
* ECDH compute shared secret
*
* [out] secret: on success, holds the shared secret, as a big-endian integer
* [in] priv: our private key as a big-endian integer
* [in] pub: the peer's public key, as two big-endian integers
*
* return: P256_SUCCESS on success
* P256_INVALID_PRIVKEY if priv is invalid
* P256_INVALID_PUBKEY if pub is invalid
*/
int p256_ecdh_shared_secret(uint8_t secret[32],
const uint8_t priv[32], const uint8_t pub[64]);
/*
* ECDSA sign
*
* [in] draws from p256_generate_random()
* [out] sig: on success, holds the signature, as two big-endian integers
* [in] priv: our private key as a big-endian integer
* [in] hash: the hash of the message to be signed
* [in] hlen: the size of hash in bytes
*
* return: P256_SUCCESS on success
* P256_RANDOM_FAILED on failure
* P256_INVALID_PRIVKEY if priv is invalid
*/
int p256_ecdsa_sign(uint8_t sig[64], const uint8_t priv[32],
const uint8_t *hash, size_t hlen);
/*
* ECDSA verify
*
* [in] sig: the signature to be verified, as two big-endian integers
* [in] pub: the associated public key, as two big-endian integers
* [in] hash: the hash of the message that was signed
* [in] hlen: the size of hash in bytes
*
* return: P256_SUCCESS on success - the signature was verified as valid
* P256_INVALID_PUBKEY if pub is invalid
* P256_INVALID_SIGNATURE if the signature was found to be invalid
*/
int p256_ecdsa_verify(const uint8_t sig[64], const uint8_t pub[64],
const uint8_t *hash, size_t hlen);
/*
* Public key validation
*
* Note: you never need to call this function, as all other functions always
* validate their input; however it's availabe if you want to validate the key
* without performing an operation.
*
* [in] pub: the public key, as two big-endian integers
*
* return: P256_SUCCESS if the key is valid
* P256_INVALID_PUBKEY if pub is invalid
*/
int p256_validate_pubkey(const uint8_t pub[64]);
/*
* Private key validation
*
* Note: you never need to call this function, as all other functions always
* validate their input; however it's availabe if you want to validate the key
* without performing an operation.
*
* [in] priv: the private key, as a big-endian integer
*
* return: P256_SUCCESS if the key is valid
* P256_INVALID_PRIVKEY if priv is invalid
*/
int p256_validate_privkey(const uint8_t priv[32]);
/*
* Compute public key from private key
*
* [out] pub: the associated public key, as two big-endian integers
* [in] priv: the private key, as a big-endian integer
*
* return: P256_SUCCESS on success
* P256_INVALID_PRIVKEY if priv is invalid
*/
int p256_public_from_private(uint8_t pub[64], const uint8_t priv[32]);
#ifdef __cplusplus
}
#endif
#endif /* P256_M_H */