text: /* ecc_dh.h - TinyCrypt interface to EC-DSA implementation */
  
  /*
   * Copyright (c) 2014, Kenneth MacKay
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * * Redistributions of source code must retain the above copyright notice, this
   *   list of conditions and the following disclaimer.
   *
   * * Redistributions in binary form must reproduce the above copyright notice,
   *   this list of conditions and the following disclaimer in the documentation
   *   and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS 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 ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  /*
   * Copyright (C) 2017 by Intel Corporation, All Rights Reserved.
   *
   *  Redistribution and use in source and binary forms, with or without
   *  modification, are permitted provided that the following conditions are met:
   *
   *    - Redistributions of source code must retain the above copyright notice,
   *     this list of conditions and the following disclaimer.
   *
   *    - Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   *    - Neither the name of Intel Corporation nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS 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 ADVISED OF THE
   *  POSSIBILITY OF SUCH DAMAGE.
   */
  
  /**
   * @file
   * @brief -- Interface to EC-DSA implementation.
   *
   *  Overview: This software is an implementation of EC-DSA. This implementation
   *            uses curve NIST p-256.
   *
   *  Security: The curve NIST p-256 provides approximately 128 bits of security.
   *
   *  Usage:  - To sign: Compute a hash of the data you wish to sign (SHA-2 is
   *          recommended) and pass it in to ecdsa_sign function along with your
   *          private key and a random number. You must use a new non-predictable
   *          random number to generate each new signature.
   *          - To verify a signature: Compute the hash of the signed data using
   *          the same hash as the signer and pass it to this function along with
   *          the signer's public key and the signature values (r and s).
   */
  
  #ifndef __TC_ECC_DSA_H__
  #define __TC_ECC_DSA_H__
  
  #include "ecc.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * @brief Generate an ECDSA signature for a given hash value.
   * @return returns TC_CRYPTO_SUCCESS (1) if the signature generated successfully
   *         returns TC_CRYPTO_FAIL (0) if an error occurred.
   *
   * @param p_private_key IN -- Your private key.
   * @param p_message_hash IN -- The hash of the message to sign.
   * @param p_hash_size IN -- The size of p_message_hash in bytes.
   * @param p_signature OUT -- Will be filled in with the signature value. Must be
   * at least 2 * curve size long (for secp256r1, signature must be 64 bytes long).
   *
   * @warning A cryptographically-secure PRNG function must be set (using
   * uECC_set_rng()) before calling uECC_sign().
   * @note Usage: Compute a hash of the data you wish to sign (SHA-2 is
   * recommended) and pass it in to this function along with your private key.
   * @note side-channel countermeasure: algorithm strengthened against timing
   * attack.
   */
  int uECC_sign(const uint8_t *p_private_key, const uint8_t *p_message_hash,
                unsigned p_hash_size, uint8_t *p_signature, uECC_Curve curve);
  
  #ifdef ENABLE_TESTS
  /*
   * THIS FUNCTION SHOULD BE CALLED FOR TEST PURPOSES ONLY.
   * Refer to uECC_sign() function for real applications.
   */
  int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash,
                       unsigned int hash_size, uECC_word_t *k, uint8_t *signature,
                       uECC_Curve curve);
  #endif
  
  /**
   * @brief Verify an ECDSA signature.
   * @return returns TC_SUCCESS (1) if the signature is valid
   * 	   returns TC_FAIL (0) if the signature is invalid.
   *
   * @param p_public_key IN -- The signer's public key.
   * @param p_message_hash IN -- The hash of the signed data.
   * @param p_hash_size IN -- The size of p_message_hash in bytes.
   * @param p_signature IN -- The signature values.
   *
   * @note Usage: Compute the hash of the signed data using the same hash as the
   * signer and pass it to this function along with the signer's public key and
   * the signature values (hash_size and signature).
   */
  int uECC_verify(const uint8_t *p_public_key, const uint8_t *p_message_hash,
                  unsigned int p_hash_size, const uint8_t *p_signature, uECC_Curve curve);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* __TC_ECC_DSA_H__ */
  