crypto/ecc.h

   1 /*
   2  * Copyright (c) 2013, Kenneth MacKay
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
   8  *  * Redistributions of source code must retain the above copyright
   9  *   notice, this list of conditions and the following disclaimer.
  10  *  * Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  15  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  16  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  17  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  18  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  19  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  20  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26 #ifndef _CRYPTO_ECC_H
  27 #define _CRYPTO_ECC_H
  28
  29 #define ECC_MAX_DIGITS  4 /* 256 */
  30
  31 #define ECC_DIGITS_TO_BYTES_SHIFT 3
  32
  33 /**
  34  * ecc_is_key_valid() - Validate a given ECDH private key
  35  *
  36  * @curve_id:           id representing the curve to use
  37  * @ndigits:            curve's number of digits
  38  * @private_key:        private key to be used for the given curve
  39  * @private_key_len:    private key length
  40  *
  41  * Returns 0 if the key is acceptable, a negative value otherwise
  42  */
  43 int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
  44                      const u64 *private_key, unsigned int private_key_len);
  45
  46 /**
  47  * ecc_gen_privkey() -  Generates an ECC private key.
  48  * The private key is a random integer in the range 0 < random < n, where n is a
  49  * prime that is the order of the cyclic subgroup generated by the distinguished
  50  * point G.
  51  * @curve_id:           id representing the curve to use
  52  * @ndigits:            curve number of digits
  53  * @private_key:        buffer for storing the generated private key
  54  *
  55  * Returns 0 if the private key was generated successfully, a negative value
  56  * if an error occurred.
  57  */
  58 int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey);
  59
  60 /**
  61  * ecc_make_pub_key() - Compute an ECC public key
  62  *
  63  * @curve_id:           id representing the curve to use
  64  * @ndigits:            curve's number of digits
  65  * @private_key:        pregenerated private key for the given curve
  66  * @public_key:         buffer for storing the generated public key
  67  *
  68  * Returns 0 if the public key was generated successfully, a negative value
  69  * if an error occurred.
  70  */
  71 int ecc_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
  72                      const u64 *private_key, u64 *public_key);
  73
  74 /**
  75  * crypto_ecdh_shared_secret() - Compute a shared secret
  76  *
  77  * @curve_id:           id representing the curve to use
  78  * @ndigits:            curve's number of digits
  79  * @private_key:        private key of part A
  80  * @public_key:         public key of counterpart B
  81  * @secret:             buffer for storing the calculated shared secret
  82  *
  83  * Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
  84  * before using it for symmetric encryption or HMAC.
  85  *
  86  * Returns 0 if the shared secret was generated successfully, a negative value
  87  * if an error occurred.
  88  */
  89 int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
  90                               const u64 *private_key, const u64 *public_key,
  91                               u64 *secret);
  92 #endif