text: /* LibTomCrypt, modular cryptographic library -- Tom St Denis
   *
   * LibTomCrypt is a library that provides various cryptographic
   * algorithms in a highly modular and flexible manner.
   *
   * The library is free for all purposes without any express
   * guarantee it works.
   */
  #include "tomcrypt.h"
  
  
  #ifdef LTC_MDSA
  
  /**
    Import DSA's p, q & g from dsaparam
  
        dsaparam data: openssl dsaparam -outform DER -out dsaparam.der 2048
  
    @param dsaparam    The DSA param DER encoded data
    @param dsaparamlen The length of dhparam data
    @param key         [out] the destination for the imported key
    @return CRYPT_OK if successful.
  */
  int dsa_set_pqg_dsaparam(const unsigned char *dsaparam, unsigned long dsaparamlen,
                           dsa_key *key)
  {
     int err, stat;
  
     LTC_ARGCHK(dsaparam    != NULL);
     LTC_ARGCHK(key         != NULL);
     LTC_ARGCHK(ltc_mp.name != NULL);
  
     /* init key */
     err = mp_init_multi(&key->p, &key->g, &key->q, &key->x, &key->y, NULL);
     if (err != CRYPT_OK) return err;
  
     if ((err = der_decode_sequence_multi(dsaparam, dsaparamlen,
                                          LTC_ASN1_INTEGER, 1UL, key->p,
                                          LTC_ASN1_INTEGER, 1UL, key->q,
                                          LTC_ASN1_INTEGER, 1UL, key->g,
                                          LTC_ASN1_EOL,     0UL, NULL)) != CRYPT_OK) {
        goto LBL_ERR;
     }
  
     key->qord = mp_unsigned_bin_size(key->q);
  
     /* quick p, q, g validation, without primality testing */
     if ((err = dsa_int_validate_pqg(key, &stat)) != CRYPT_OK) {
        goto LBL_ERR;
     }
     if (stat == 0) {
        err = CRYPT_INVALID_PACKET;
        goto LBL_ERR;
     }
  
     return CRYPT_OK;
  
  LBL_ERR:
     dsa_free(key);
     return err;
  }
  
  #endif
  
  /* ref:         tag: v1.18.2, master */
  /* git commit:  7e7eb695d581782f04b24dc444cbfde86af59853 */
  /* commit time: 2018-07-01 22:49:01 +0200 */
  