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_CURVE_NIST_P192_DIGITS  3
  30 #define ECC_CURVE_NIST_P256_DIGITS  4
  31 #define ECC_MAX_DIGITS              ECC_CURVE_NIST_P256_DIGITS
  32
  33 #define ECC_DIGITS_TO_BYTES_SHIFT 3
  34
  35 /**
  36  * ecc_is_key_valid() - Validate a given ECDH private key
  37  *
  38  * @curve_id:           id representing the curve to use
  39  * @ndigits:            curve's number of digits
  40  * @private_key:        private key to be used for the given curve
  41  * @private_key_len:    private key length
  42  *
  43  * Returns 0 if the key is acceptable, a negative value otherwise
  44  */
  45 int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
  46                      const u64 *private_key, unsigned int private_key_len);
  47
  48 /**
  49  * ecc_gen_privkey() -  Generates an ECC private key.
  50  * The private key is a random integer in the range 0 < random < n, where n is a
  51  * prime that is the order of the cyclic subgroup generated by the distinguished
  52  * point G.
  53  * @curve_id:           id representing the curve to use
  54  * @ndigits:            curve number of digits
  55  * @private_key:        buffer for storing the generated private key
  56  *
  57  * Returns 0 if the private key was generated successfully, a negative value
  58  * if an error occurred.
  59  */
  60 int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey);
  61
  62 /**
  63  * ecc_make_pub_key() - Compute an ECC public key
  64  *
  65  * @curve_id:           id representing the curve to use
  66  * @ndigits:            curve's number of digits
  67  * @private_key:        pregenerated private key for the given curve
  68  * @public_key:         buffer for storing the generated public key
  69  *
  70  * Returns 0 if the public key was generated successfully, a negative value
  71  * if an error occurred.
  72  */
  73 int ecc_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
  74                      const u64 *private_key, u64 *public_key);
  75
  76 /**
  77  * crypto_ecdh_shared_secret() - Compute a shared secret
  78  *
  79  * @curve_id:           id representing the curve to use
  80  * @ndigits:            curve's number of digits
  81  * @private_key:        private key of part A
  82  * @public_key:         public key of counterpart B
  83  * @secret:             buffer for storing the calculated shared secret
  84  *
  85  * Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
  86  * before using it for symmetric encryption or HMAC.
  87  *
  88  * Returns 0 if the shared secret was generated successfully, a negative value
  89  * if an error occurred.
  90  */
  91 int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
  92                               const u64 *private_key, const u64 *public_key,
  93                               u64 *secret);
  94 #endif