/*
 * Copyright (c) 2014, Institute for Pervasive Computing, ETH Zurich.
 * All rights reserved.
 *
 * Author: Andreas Dröscher <contiki@anticat.ch>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
 */
/**
 * \addtogroup cc2538-ecc
 * @{
 *
 * \defgroup cc2538-ecc-algo cc2538 ECC Algorithms
 *
 * This is a implementation of ECDH, ECDSA sign and ECDSA verify. It
 * uses ecc-driver to communicate with the PKA. It uses continuations
 * to free the main CPU / thread while the PKA is calculating.
 *
 * \note
 * Only one request can be processed at a time.
 * Maximal supported key length is 384bit (12 words).
 * @{
 *
 * \file
 * Header file for the cc2538 ECC Algorithms
 */
#ifndef ECC_ALGORITHM_H_
#define ECC_ALGORITHM_H_

#include "bignum-driver.h"
#include "ecc-driver.h"

typedef struct  {
  /* Containers for the State */
  struct pt      pt;
  struct process *process;

  /* Input Variables */
  uint32_t    a[12];            /**< Left Number */
  uint32_t    b[12];            /**< Right Number */
  uint8_t     size;             /**< Length of a and b */

  /* Output Variables */
  uint8_t     result;           /**< Result Code */
} ecc_compare_state_t;

/**
 * \brief Do a compare of two big numbers
 *
 * This function can be used for ECDH as well as
 * Calculating a Public Key for ECDSA
 */
PT_THREAD(ecc_compare(ecc_compare_state_t *state));

typedef struct {
  /* Containers for the State */
  struct pt      pt;
  struct process *process;

  /* Input Variables */
  ecc_curve_info_t *curve_info; /**< Curve defining the CyclicGroup */
  ec_point_t       point_in;    /**< Generator Point */
  uint32_t         secret[12];  /**< Secret */

  /* Variables Holding intermediate data (initialized/used internally) */
  uint32_t         rv;          /**< Address of Next Result in PKA SRAM */

  /* Output Variables */
  uint8_t          result;      /**< Result Code */
  ec_point_t       point_out;   /**< Generated Point */
} ecc_multiply_state_t;

/**
 * \brief Do a Multiplication on a EC
 *
 * This function can be used for ECDH as well as
 * Calculating a Public Key for ECDSA
 */
PT_THREAD(ecc_multiply(ecc_multiply_state_t *state));

typedef struct {
  /* Containers for the State */
  struct pt      pt;
  struct process *process;

  /* Input Variables */
  ecc_curve_info_t *curve_info; /**< Curve defining the CyclicGroup */
  uint32_t    secret[12];       /**< Secret Key */
  uint32_t    k_e[12];          /**< Ephemeral Key */
  uint32_t    hash[12];         /**< Hash to be signed */

  /* Variables Holding intermediate data (initialized/used internally) */
  uint32_t    rv;               /**< Address of Next Result in PKA SRAM */
  uint32_t    k_e_inv[12];      /**< Inverted ephemeral Key */
  uint32_t    len;              /**< Length of intermediate Result */

  /* Output Variables */
  uint8_t     result;           /**< Result Code */
  ec_point_t  point_r;          /**< Signature R (x coordinate) */
  uint32_t    signature_s[24];  /**< Signature S */
} ecc_dsa_sign_state_t;

/**
 * \brief Sign a Hash
 *
 * This function has to be called several times until the
 * pt state is EXIT
 * If the result code is 0 (SUCCESS) the signature can be
 * read from point_r and signature_s
 */
PT_THREAD(ecc_dsa_sign(ecc_dsa_sign_state_t *state));

typedef struct {
  /* Containers for the State */
  struct pt      pt;
  struct process *process;

  /* Input Variables */
  ecc_curve_info_t *curve_info; /**< Curve defining the CyclicGroup */
  uint32_t    signature_r[12];  /**< Signature R */
  uint32_t    signature_s[12];  /**< Signature S */
  uint32_t    hash[12];         /**< Hash to be signed */
  ec_point_t  public;           /**< Signature R (x coordinate) */

  /* Variables Holding intermediate data (initialized/used internally) */
  uint32_t    rv;               /**< Address of Next Result in PKA SRAM */
  uint32_t    s_inv[12];        /**< Inverted ephemeral Key */
  uint32_t    u1[24];           /**< Intermediate result */
  uint32_t    u2[24];           /**< Intermediate result */
  ec_point_t  p1;               /**< Intermediate result */
  ec_point_t  p2;               /**< Intermediate result */
  uint32_t    len;              /**< Length of intermediate Result */

  /* Output Variables */
  uint8_t     result;           /**< Result Code */
} ecc_dsa_verify_state_t;

/**
 * \brief Verify Signature
 *
 * This function has to be called several times until the
 * pt state is EXIT
 * If the result code is 0 (SUCCESS) the verification
 * was success full.
 * \note some error codes signal internal errors
 * and others signal falls signatures.
 */
PT_THREAD(ecc_dsa_verify(ecc_dsa_verify_state_t *state));

#endif /* ECC_ALGORITHM_H_ */

/**
 * @}
 * @}
 */