contrib/lax_der_privatekey_parsing.h

   1 /**********************************************************************
   2  * Copyright (c) 2014, 2015 Pieter Wuille                             *
   3  * Distributed under the MIT software license, see the accompanying   *
   4  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
   5  **********************************************************************/
   6
   7 /****
   8  * Please do not link this file directly. It is not part of the libsecp256k1
   9  * project and does not promise any stability in its API, functionality or
  10  * presence. Projects which use this code should instead copy this header
  11  * and its accompanying .c file directly into their codebase.
  12  ****/
  13
  14 /* This file contains code snippets that parse DER private keys with
  15  * various errors and violations.  This is not a part of the library
  16  * itself, because the allowed violations are chosen arbitrarily and
  17  * do not follow or establish any standard.
  18  *
  19  * It also contains code to serialize private keys in a compatible
  20  * manner.
  21  *
  22  * These functions are meant for compatibility with applications
  23  * that require BER encoded keys. When working with secp256k1-specific
  24  * code, the simple 32-byte private keys normally used by the
  25  * library are sufficient.
  26  */
  27
  28 #ifndef SECP256K1_CONTRIB_BER_PRIVATEKEY_H
  29 #define SECP256K1_CONTRIB_BER_PRIVATEKEY_H
  30
  31 #include <secp256k1.h>
  32
  33 #ifdef __cplusplus
  34 extern "C" {
  35 #endif
  36
  37 /** Export a private key in DER format.
  38  *
  39  *  Returns: 1 if the private key was valid.
  40  *  Args: ctx:        pointer to a context object, initialized for signing (cannot
  41  *                    be NULL)
  42  *  Out: privkey:     pointer to an array for storing the private key in BER.
  43  *                    Should have space for 279 bytes, and cannot be NULL.
  44  *       privkeylen:  Pointer to an int where the length of the private key in
  45  *                    privkey will be stored.
  46  *  In:  seckey:      pointer to a 32-byte secret key to export.
  47  *       compressed:  1 if the key should be exported in
  48  *                    compressed format, 0 otherwise
  49  *
  50  *  This function is purely meant for compatibility with applications that
  51  *  require BER encoded keys. When working with secp256k1-specific code, the
  52  *  simple 32-byte private keys are sufficient.
  53  *
  54  *  Note that this function does not guarantee correct DER output. It is
  55  *  guaranteed to be parsable by secp256k1_ec_privkey_import_der
  56  */
  57 SECP256K1_WARN_UNUSED_RESULT int ec_privkey_export_der(
  58     const secp256k1_context* ctx,
  59     unsigned char *privkey,
  60     size_t *privkeylen,
  61     const unsigned char *seckey,
  62     int compressed
  63 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
  64
  65 /** Import a private key in DER format.
  66  * Returns: 1 if a private key was extracted.
  67  * Args: ctx:        pointer to a context object (cannot be NULL).
  68  * Out:  seckey:     pointer to a 32-byte array for storing the private key.
  69  *                   (cannot be NULL).
  70  * In:   privkey:    pointer to a private key in DER format (cannot be NULL).
  71  *       privkeylen: length of the DER private key pointed to be privkey.
  72  *
  73  * This function will accept more than just strict DER, and even allow some BER
  74  * violations. The public key stored inside the DER-encoded private key is not
  75  * verified for correctness, nor are the curve parameters. Use this function
  76  * only if you know in advance it is supposed to contain a secp256k1 private
  77  * key.
  78  */
  79 SECP256K1_WARN_UNUSED_RESULT int ec_privkey_import_der(
  80     const secp256k1_context* ctx,
  81     unsigned char *seckey,
  82     const unsigned char *privkey,
  83     size_t privkeylen
  84 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
  85
  86 #ifdef __cplusplus
  87 }
  88 #endif
  89
  90 #endif /* SECP256K1_CONTRIB_BER_PRIVATEKEY_H */