/*
 * Copyright (c) 2018-2020, Arm Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 */
/**
 * \file
 *
 * \brief PSA cryptography module: vendor extensions
 *
 * \note This file may not be included directly. Applications must
 * include psa/crypto.h.
 *
 * This file is reserved for vendor-specific definitions.
 */

#ifndef PSA_CRYPTO_EXTRA_H
#define PSA_CRYPTO_EXTRA_H

#include "psa/crypto_compat.h"

#ifdef __cplusplus
extern "C" {
#endif

/** \brief Declare the enrollment algorithm for a key.
 *
 * An operation on a key may indifferently use the algorithm set with
 * psa_set_key_algorithm() or with this function.
 *
 * \param[out] attributes       The attribute structure to write to.
 * \param alg2                  A second algorithm that the key may be used
 *                              for, in addition to the algorithm set with
 *                              psa_set_key_algorithm().
 *
 * \warning Setting an enrollment algorithm is not recommended, because
 *          using the same key with different algorithms can allow some
 *          attacks based on arithmetic relations between different
 *          computations made with the same key, or can escalate harmless
 *          side channels into exploitable ones. Use this function only
 *          if it is necessary to support a protocol for which it has been
 *          verified that the usage of the key with multiple algorithms
 *          is safe.
 */
static inline void psa_set_key_enrollment_algorithm(
    psa_key_attributes_t *attributes,
    psa_algorithm_t alg2)
{
    attributes->core.policy.alg2 = alg2;
}

#if defined(MBEDTLS_ECP_C)
#include <mbedtls/ecp.h>

/** Convert an ECC curve identifier from the Mbed TLS encoding to PSA.
 *
 * \note This function is provided solely for the convenience of
 *       Mbed TLS and may be removed at any time without notice.
 *
 * \param grpid         An Mbed TLS elliptic curve identifier
 *                      (`MBEDTLS_ECP_DP_xxx`).
 * \param[out] bits     On success, the bit size of the curve.
 *
 * \return              The corresponding PSA elliptic curve identifier
 *                      (`PSA_ECC_FAMILY_xxx`).
 * \return              \c 0 on failure (\p grpid is not recognized).
 */
static inline psa_ecc_family_t mbedtls_ecc_group_to_psa( mbedtls_ecp_group_id grpid,
                                                        size_t *bits )
{
    switch( grpid )
    {
        case MBEDTLS_ECP_DP_SECP192R1:
            *bits = 192;
            return( PSA_ECC_FAMILY_SECP_R1 );
        case MBEDTLS_ECP_DP_SECP224R1:
            *bits = 224;
            return( PSA_ECC_FAMILY_SECP_R1 );
        case MBEDTLS_ECP_DP_SECP256R1:
            *bits = 256;
            return( PSA_ECC_FAMILY_SECP_R1 );
        case MBEDTLS_ECP_DP_SECP384R1:
            *bits = 384;
            return( PSA_ECC_FAMILY_SECP_R1 );
        case MBEDTLS_ECP_DP_SECP521R1:
            *bits = 521;
            return( PSA_ECC_FAMILY_SECP_R1 );
        case MBEDTLS_ECP_DP_BP256R1:
            *bits = 256;
            return( PSA_ECC_FAMILY_BRAINPOOL_P_R1 );
        case MBEDTLS_ECP_DP_BP384R1:
            *bits = 384;
            return( PSA_ECC_FAMILY_BRAINPOOL_P_R1 );
        case MBEDTLS_ECP_DP_BP512R1:
            *bits = 512;
            return( PSA_ECC_FAMILY_BRAINPOOL_P_R1 );
        case MBEDTLS_ECP_DP_CURVE25519:
            *bits = 255;
            return( PSA_ECC_FAMILY_MONTGOMERY );
        case MBEDTLS_ECP_DP_SECP192K1:
            *bits = 192;
            return( PSA_ECC_FAMILY_SECP_K1 );
        case MBEDTLS_ECP_DP_SECP224K1:
            *bits = 224;
            return( PSA_ECC_FAMILY_SECP_K1 );
        case MBEDTLS_ECP_DP_SECP256K1:
            *bits = 256;
            return( PSA_ECC_FAMILY_SECP_K1 );
        case MBEDTLS_ECP_DP_CURVE448:
            *bits = 448;
            return( PSA_ECC_FAMILY_MONTGOMERY );
        default:
            *bits = 0;
            return( 0 );
    }
}

/** Convert an ECC curve identifier from the PSA encoding to Mbed TLS.
 *
 * \note This function is provided solely for the convenience of
 *       Mbed TLS and may be removed at any time without notice.
 *
 * \param curve         A PSA elliptic curve identifier
 *                      (`PSA_ECC_FAMILY_xxx`).
 * \param byte_length   The byte-length of a private key on \p curve.
 *
 * \return              The corresponding Mbed TLS elliptic curve identifier
 *                      (`MBEDTLS_ECP_DP_xxx`).
 * \return              #MBEDTLS_ECP_DP_NONE if \c curve is not recognized.
 * \return              #MBEDTLS_ECP_DP_NONE if \p byte_length is not
 *                      correct for \p curve.
 */
//mbedtls_ecp_group_id mbedtls_ecc_group_of_psa( psa_ecc_family_t curve,
//                                               size_t byte_length );
#endif /* MBEDTLS_ECP_C */

#ifdef __cplusplus
}
#endif

#endif /* PSA_CRYPTO_EXTRA_H */