src/TortoisePlink/sshecdsag.c

   1 /*
   2  * EC key generation.
   3  */
   4
   5 #include "ssh.h"
   6
   7 /* Forward reference from sshecc.c */
   8 struct ec_point *ecp_mul(const struct ec_point *a, const Bignum b);
   9
  10 int ec_generate(struct ec_key *key, int bits, progfn_t pfn,
  11                 void *pfnparam)
  12 {
  13     struct ec_point *publicKey;
  14
  15     if (!ec_nist_alg_and_curve_by_bits(bits, &key->publicKey.curve,
  16                                        &key->signalg))
  17         return 0;
  18
  19     key->privateKey = bignum_random_in_range(One, key->publicKey.curve->w.n);
  20     if (!key->privateKey) return 0;
  21
  22     publicKey = ec_public(key->privateKey, key->publicKey.curve);
  23     if (!publicKey) {
  24         freebn(key->privateKey);
  25         key->privateKey = NULL;
  26         return 0;
  27     }
  28
  29     key->publicKey.x = publicKey->x;
  30     key->publicKey.y = publicKey->y;
  31     key->publicKey.z = NULL;
  32     sfree(publicKey);
  33
  34     return 1;
  35 }
  36
  37 int ec_edgenerate(struct ec_key *key, int bits, progfn_t pfn,
  38                   void *pfnparam)
  39 {
  40     struct ec_point *publicKey;
  41
  42     if (!ec_ed_alg_and_curve_by_bits(bits, &key->publicKey.curve,
  43                                      &key->signalg))
  44         return 0;
  45
  46     {
  47         /* EdDSA secret keys are just 32 bytes of hash preimage; the
  48          * 64-byte SHA-512 hash of that key will be used when signing,
  49          * but the form of the key stored on disk is the preimage
  50          * only. */
  51         Bignum privMax = bn_power_2(bits);
  52         if (!privMax) return 0;
  53         key->privateKey = bignum_random_in_range(Zero, privMax);
  54         freebn(privMax);
  55         if (!key->privateKey) return 0;
  56     }
  57
  58     publicKey = ec_public(key->privateKey, key->publicKey.curve);
  59     if (!publicKey) {
  60         freebn(key->privateKey);
  61         key->privateKey = NULL;
  62         return 0;
  63     }
  64
  65     key->publicKey.x = publicKey->x;
  66     key->publicKey.y = publicKey->y;
  67     key->publicKey.z = NULL;
  68     sfree(publicKey);
  69
  70     return 1;
  71 }