pd.if.org Git - zpackage/blob - libtomcrypt/src/pk/dsa/dsa_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 #include "tomcrypt.h"
  10
  11 /**
  12    @file dsa_export.c
  13    DSA implementation, export key, Tom St Denis
  14 */
  15
  16 #ifdef LTC_MDSA
  17
  18 /**
  19   Export a DSA key to a binary packet
  20   @param out    [out] Where to store the packet
  21   @param outlen [in/out] The max size and resulting size of the packet
  22   @param type   The type of key to export (PK_PRIVATE or PK_PUBLIC)
  23   @param key    The key to export
  24   @return CRYPT_OK if successful
  25 */
  26 int dsa_export(unsigned char *out, unsigned long *outlen, int type, dsa_key *key)
  27 {
  28    unsigned long zero=0;
  29    int err, std;
  30
  31    LTC_ARGCHK(out    != NULL);
  32    LTC_ARGCHK(outlen != NULL);
  33    LTC_ARGCHK(key    != NULL);
  34
  35    std = type & PK_STD;
  36    type &= ~PK_STD;
  37
  38    /* can we store the static header?  */
  39    if (type == PK_PRIVATE && key->type != PK_PRIVATE) {
  40       return CRYPT_PK_TYPE_MISMATCH;
  41    }
  42
  43    if (type != PK_PUBLIC && type != PK_PRIVATE) {
  44       return CRYPT_INVALID_ARG;
  45    }
  46
  47    if (type == PK_PRIVATE) {
  48       if (std) {
  49           return der_encode_sequence_multi(out, outlen,
  50                                          LTC_ASN1_SHORT_INTEGER, 1UL, &zero,
  51                                          LTC_ASN1_INTEGER,      1UL, key->p,
  52                                          LTC_ASN1_INTEGER,      1UL, key->q,
  53                                          LTC_ASN1_INTEGER,      1UL, key->g,
  54                                          LTC_ASN1_INTEGER,      1UL, key->y,
  55                                          LTC_ASN1_INTEGER,      1UL, key->x,
  56                                          LTC_ASN1_EOL,          0UL, NULL);
  57       }
  58       else {
  59           unsigned char flags[1];
  60           flags[0] = 1;
  61           return der_encode_sequence_multi(out, outlen,
  62                                          LTC_ASN1_BIT_STRING,   1UL, flags,
  63                                          LTC_ASN1_INTEGER,      1UL, key->g,
  64                                          LTC_ASN1_INTEGER,      1UL, key->p,
  65                                          LTC_ASN1_INTEGER,      1UL, key->q,
  66                                          LTC_ASN1_INTEGER,      1UL, key->y,
  67                                          LTC_ASN1_INTEGER,      1UL, key->x,
  68                                          LTC_ASN1_EOL,          0UL, NULL);
  69       }
  70    } else {
  71       if (std) {
  72           unsigned long tmplen = (unsigned long)(mp_count_bits(key->y) / 8) + 8;
  73           unsigned char* tmp = XMALLOC(tmplen);
  74           ltc_asn1_list int_list[3];
  75
  76           if (tmp == NULL) {
  77               return CRYPT_MEM;
  78           }
  79
  80           err = der_encode_integer(key->y, tmp, &tmplen);
  81           if (err != CRYPT_OK) {
  82               goto error;
  83           }
  84
  85           LTC_SET_ASN1(int_list, 0, LTC_ASN1_INTEGER, key->p, 1UL);
  86           LTC_SET_ASN1(int_list, 1, LTC_ASN1_INTEGER, key->q, 1UL);
  87           LTC_SET_ASN1(int_list, 2, LTC_ASN1_INTEGER, key->g, 1UL);
  88
  89           err = der_encode_subject_public_key_info(out, outlen, PKA_DSA, tmp,
  90               tmplen, LTC_ASN1_SEQUENCE, int_list,
  91               sizeof(int_list) / sizeof(int_list[0]));
  92
  93 error:
  94           XFREE(tmp);
  95           return err;
  96       }
  97       else {
  98           unsigned char flags[1];
  99           flags[0] = 0;
 100           return der_encode_sequence_multi(out, outlen,
 101                                      LTC_ASN1_BIT_STRING,   1UL, flags,
 102                                      LTC_ASN1_INTEGER,      1UL, key->g,
 103                                      LTC_ASN1_INTEGER,      1UL, key->p,
 104                                      LTC_ASN1_INTEGER,      1UL, key->q,
 105                                      LTC_ASN1_INTEGER,      1UL, key->y,
 106                                      LTC_ASN1_EOL,          0UL, NULL);
 107       }
 108    }
 109 }
 110
 111 #endif
 112
 113
 114 /* ref:         $Format:%D$ */
 115 /* git commit:  $Format:%H$ */
 116 /* commit time: $Format:%ai$ */