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 * Copyright (c) 2019 - 2020, Nordic Semiconductor ASA
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 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
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 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
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 * 4. This software, with or without modification, must only be used with a
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 *    engineered, decompiled, modified and/or disassembled.
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/**@file
 * @defgroup nrf_oberon_ecdsa ECDSA APIs
 * @ingroup nrf_oberon
 * @{
 * @brief Type declarations and APIs to do Elliptic Curve Digital Signature Algorith using the
 * NIST secp256r1 curve.
 */
#ifndef OCRYPTO_ECDSA_P256_H
#define OCRYPTO_ECDSA_P256_H

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

#ifdef __cplusplus
extern "C" {
#endif

/**
 * ECDSA P-256 public key generation.
 *
 * Given a secret key @p sk the corresponding public key is computed and put
 * into @p pk.
 *
 * @param[out] pk Generated public key.
 * @param      sk Secret key. Must be pre-filled with random data.
 *
 * @retval 0  If @p sk is a valid secret key.
 * @retval -1 Otherwise.
 */
int ocrypto_ecdsa_p256_public_key(
    uint8_t pk[64],
    const uint8_t sk[32]);

/**
 * ECDSA P-256 signature generation.
 *
 * The message @p m is signed using the secret key @p sk and the ephemeral
 * session key @p ek. The signature is put into @p sig.
 *
 * @param[out] sig  Generated signature.
 * @param      m    Input message.
 * @param      mlen Length of @p m.
 * @param      sk   Secret key.
 * @param      ek   Ephemeral session key.
 *
 * @retval 0  If @p ek is a valid session key.
 * @retval -1 Otherwise.
 */
int ocrypto_ecdsa_p256_sign(
    uint8_t sig[64],
    const uint8_t *m, size_t mlen,
    const uint8_t sk[32],
    const uint8_t ek[32]);

/**
 * ECDSA P-256 signature generation from SHA256 hash.
 *
 * The message hash @p hash is signed using the secret key @p sk and the ephemeral
 * session key @p ek. The signature is put into @p sig.
 *
 * @param[out] sig  Generated signature.
 * @param      hash Input hash.
 * @param      sk   Secret key.
 * @param      ek   Ephemeral session key.
 *
 * @retval 0  If @p ek is a valid session key.
 * @retval -1 Otherwise.
 */
int ocrypto_ecdsa_p256_sign_hash(
    uint8_t sig[64],
    const uint8_t hash[32],
    const uint8_t sk[32],
    const uint8_t ek[32]);

/**
 * ECDSA P-256 signature verification.
 *
 * The signature @p sig of the input message @p m is verified using the signer's
 * public key @p pk.
 *
 * @param sig  Input signature.
 * @param m    Input message.
 * @param mlen Length of @p m.
 * @param pk   Signer's public key.
 *
 * @retval 0  If the signature is valid.
 * @retval -1 Otherwise.
 */
int ocrypto_ecdsa_p256_verify(
    const uint8_t sig[64],
    const uint8_t *m, size_t mlen,
    const uint8_t pk[64]);

/**
 * ECDSA P-256 signature verification from SHA256 hash.
 *
 * The signature @p sig of the message hash @p hash is verified using the signer's
 * public key @p pk.
 *
 * @param sig  Input signature.
 * @param hash Input hash.
 * @param pk   Signer's public key.
 *
 * @retval 0  If the signature is valid.
 * @retval -1 Otherwise.
 */
int ocrypto_ecdsa_p256_verify_hash(
    const uint8_t sig[64],
    const uint8_t hash[32],
    const uint8_t pk[64]);

#ifdef __cplusplus
}
#endif

#endif /* #ifndef OCRYPTO_ECDSA_P256_H */

/** @} */