--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/dh/dh_set.c	Fri Feb 09 21:44:05 2018 +0800
@@ -0,0 +1,124 @@
+/* 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_MDH
+
+/**
+  Import DH key parts p and g from raw numbers
+
+  @param p       DH's p (prime)
+  @param plen    DH's p's length
+  @param g       DH's g (group)
+  @param glen    DH's g's length
+  @param key     [out] the destination for the imported key
+  @return CRYPT_OK if successful
+*/
+int dh_set_pg(const unsigned char *p, unsigned long plen,
+              const unsigned char *g, unsigned long glen,
+              dh_key *key)
+{
+   int err;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(p           != NULL);
+   LTC_ARGCHK(g           != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+
+   if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((err = mp_read_unsigned_bin(key->base, (unsigned char*)g, glen)) != CRYPT_OK)     { goto LBL_ERR; }
+   if ((err = mp_read_unsigned_bin(key->prime, (unsigned char*)p, plen)) != CRYPT_OK)  { goto LBL_ERR; }
+
+   return CRYPT_OK;
+
+LBL_ERR:
+   dh_free(key);
+   return err;
+}
+
+/**
+  Import DH key parts p and g from built-in DH groups
+
+  @param groupsize  The size of the DH group to use
+  @param key        [out] Where the newly created DH key will be stored
+  @return CRYPT_OK if successful, note: on error all allocated memory will be freed automatically.
+*/
+int dh_set_pg_groupsize(int groupsize, dh_key *key)
+{
+   int err, i;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+   LTC_ARGCHK(groupsize   > 0);
+
+   for (i = 0; (groupsize > ltc_dh_sets[i].size) && (ltc_dh_sets[i].size != 0); i++);
+   if (ltc_dh_sets[i].size == 0) return CRYPT_INVALID_KEYSIZE;
+
+   if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
+      return err;
+   }
+   if ((err = mp_read_radix(key->base, ltc_dh_sets[i].base, 16)) != CRYPT_OK)  { goto LBL_ERR; }
+   if ((err = mp_read_radix(key->prime, ltc_dh_sets[i].prime, 16)) != CRYPT_OK) { goto LBL_ERR; }
+
+   return CRYPT_OK;
+
+LBL_ERR:
+   dh_free(key);
+   return err;
+}
+
+/**
+  Import DH public or private key part from raw numbers
+
+     NB: The p & g parts must be set beforehand
+
+  @param in      The key-part to import, either public or private.
+  @param inlen   The key-part's length
+  @param type    Which type of key (PK_PRIVATE or PK_PUBLIC)
+  @param key     [out] the destination for the imported key
+  @return CRYPT_OK if successful
+*/
+int dh_set_key(const unsigned char *in, unsigned long inlen, int type, dh_key *key)
+{
+   int err;
+
+   LTC_ARGCHK(key         != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+
+   if (type == PK_PRIVATE) {
+      key->type = PK_PRIVATE;
+      if ((err = mp_read_unsigned_bin(key->x, (unsigned char*)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
+      if ((err = mp_exptmod(key->base, key->x, key->prime, key->y)) != CRYPT_OK)       { goto LBL_ERR; }
+   }
+   else {
+      key->type = PK_PUBLIC;
+      if ((err = mp_read_unsigned_bin(key->y, (unsigned char*)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
+   }
+
+   /* check public key */
+   if ((err = dh_check_pubkey(key)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+
+   return CRYPT_OK;
+
+LBL_ERR:
+   dh_free(key);
+   return err;
+}
+
+#endif /* LTC_MDH */
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */