pd.if.org Git - zpackage/blob - libtomcrypt/src/pk/dh/dh_export.c

   1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
   2  *
   3  * LibTomCrypt is a library that provides various cryptographic
   4  * algorithms in a highly modular and flexible manner.
   5  *
   6  * The library is free for all purposes without any express
   7  * guarantee it works.
   8  */
   9
  10 #include "tomcrypt.h"
  11
  12 #ifdef LTC_MDH
  13
  14 /**
  15   Export a DH key to a binary packet
  16   @param out    [out] The destination for the key
  17   @param outlen [in/out] The max size and resulting size of the DH key
  18   @param type   Which type of key (PK_PRIVATE or PK_PUBLIC)
  19   @param key    The key you wish to export
  20   @return CRYPT_OK if successful
  21 */
  22 int dh_export(unsigned char *out, unsigned long *outlen, int type, dh_key *key)
  23 {
  24    unsigned char flags[1];
  25    int err;
  26    unsigned long version = 0;
  27
  28    LTC_ARGCHK(out    != NULL);
  29    LTC_ARGCHK(outlen != NULL);
  30    LTC_ARGCHK(key    != NULL);
  31
  32    if (type == PK_PRIVATE) {
  33       /* export x - private key */
  34       flags[0] = 1;
  35       err = der_encode_sequence_multi(out, outlen,
  36                                 LTC_ASN1_SHORT_INTEGER, 1UL, &version,
  37                                 LTC_ASN1_BIT_STRING,    1UL, flags,
  38                                 LTC_ASN1_INTEGER,       1UL, key->prime,
  39                                 LTC_ASN1_INTEGER,       1UL, key->base,
  40                                 LTC_ASN1_INTEGER,       1UL, key->x,
  41                                 LTC_ASN1_EOL,           0UL, NULL);
  42    }
  43    else {
  44       /* export y - public key */
  45       flags[0] = 0;
  46       err = der_encode_sequence_multi(out, outlen,
  47                                 LTC_ASN1_SHORT_INTEGER, 1UL, &version,
  48                                 LTC_ASN1_BIT_STRING,    1UL, flags,
  49                                 LTC_ASN1_INTEGER,       1UL, key->prime,
  50                                 LTC_ASN1_INTEGER,       1UL, key->base,
  51                                 LTC_ASN1_INTEGER,       1UL, key->y,
  52                                 LTC_ASN1_EOL,           0UL, NULL);
  53    }
  54
  55    return err;
  56 }
  57
  58 #endif /* LTC_MDH */
  59
  60 /* ref:         $Format:%D$ */
  61 /* git commit:  $Format:%H$ */
  62 /* commit time: $Format:%ai$ */