version 0.3.33

[fms.git] / libs / libtomcrypt / pk / rsa / rsa_make_key.c

diff --git a/libs/libtomcrypt/pk/rsa/rsa_make_key.c b/libs/libtomcrypt/pk/rsa/rsa_make_key.c
new file mode 100644 (file)
index 0000000..bd2a29b
--- /dev/null
+++ b/libs/libtomcrypt/pk/rsa/rsa_make_key.c
@@ -0,0 +1,112 @@
+/* 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.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
+ */
+#include "tomcrypt.h"
+
+/**
+  @file rsa_make_key.c
+  RSA key generation, Tom St Denis
+*/  
+
+#ifdef MRSA
+
+/** 
+   Create an RSA key
+   @param prng     An active PRNG state
+   @param wprng    The index of the PRNG desired
+   @param size     The size of the modulus (key size) desired (octets)
+   @param e        The "e" value (public key).  e==65537 is a good choice
+   @param key      [out] Destination of a newly created private key pair
+   @return CRYPT_OK if successful, upon error all allocated ram is freed
+*/
+int rsa_make_key(prng_state *prng, int wprng, int size, long e, rsa_key *key)
+{
+   void *p, *q, *tmp1, *tmp2, *tmp3;
+   int    err;
+
+   LTC_ARGCHK(ltc_mp.name != NULL);
+   LTC_ARGCHK(key         != NULL);
+
+   if ((size < (MIN_RSA_SIZE/8)) || (size > (MAX_RSA_SIZE/8))) {
+      return CRYPT_INVALID_KEYSIZE;
+   }
+
+   if ((e < 3) || ((e & 1) == 0)) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, &tmp3, NULL)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* make primes p and q (optimization provided by Wayne Scott) */
+   if ((err = mp_set_int(tmp3, e)) != CRYPT_OK)                      { goto errkey; }  /* tmp3 = e */
+
+   /* make prime "p" */
+   do {
+       if ((err = rand_prime( p, size/2, prng, wprng)) != CRYPT_OK)  { goto errkey; }
+       if ((err = mp_sub_d( p, 1,  tmp1)) != CRYPT_OK)               { goto errkey; }  /* tmp1 = p-1 */
+       if ((err = mp_gcd( tmp1,  tmp3,  tmp2)) != CRYPT_OK)          { goto errkey; }  /* tmp2 = gcd(p-1, e) */
+   } while (mp_cmp_d( tmp2, 1) != 0);                                                  /* while e divides p-1 */
+
+   /* make prime "q" */
+   do {
+       if ((err = rand_prime( q, size/2, prng, wprng)) != CRYPT_OK)  { goto errkey; }
+       if ((err = mp_sub_d( q, 1,  tmp1)) != CRYPT_OK)               { goto errkey; } /* tmp1 = q-1 */
+       if ((err = mp_gcd( tmp1,  tmp3,  tmp2)) != CRYPT_OK)          { goto errkey; } /* tmp2 = gcd(q-1, e) */
+   } while (mp_cmp_d( tmp2, 1) != 0);                                                 /* while e divides q-1 */
+
+   /* tmp1 = lcm(p-1, q-1) */
+   if ((err = mp_sub_d( p, 1,  tmp2)) != CRYPT_OK)                   { goto errkey; } /* tmp2 = p-1 */
+                                                                                      /* tmp1 = q-1 (previous do/while loop) */
+   if ((err = mp_lcm( tmp1,  tmp2,  tmp1)) != CRYPT_OK)              { goto errkey; } /* tmp1 = lcm(p-1, q-1) */
+
+   /* make key */
+   if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ, &key->dP, &key->qP, &key->p, &key->q, NULL)) != CRYPT_OK) {
+      goto errkey;
+   }
+
+   if ((err = mp_set_int( key->e, e)) != CRYPT_OK)                     { goto errkey; } /* key->e =  e */
+   if ((err = mp_invmod( key->e,  tmp1,  key->d)) != CRYPT_OK)         { goto errkey; } /* key->d = 1/e mod lcm(p-1,q-1) */
+   if ((err = mp_mul( p,  q,  key->N)) != CRYPT_OK)                    { goto errkey; } /* key->N = pq */
+
+   /* optimize for CRT now */
+   /* find d mod q-1 and d mod p-1 */
+   if ((err = mp_sub_d( p, 1,  tmp1)) != CRYPT_OK)                     { goto errkey; } /* tmp1 = q-1 */
+   if ((err = mp_sub_d( q, 1,  tmp2)) != CRYPT_OK)                     { goto errkey; } /* tmp2 = p-1 */
+   if ((err = mp_mod( key->d,  tmp1,  key->dP)) != CRYPT_OK)           { goto errkey; } /* dP = d mod p-1 */
+   if ((err = mp_mod( key->d,  tmp2,  key->dQ)) != CRYPT_OK)           { goto errkey; } /* dQ = d mod q-1 */
+   if ((err = mp_invmod( q,  p,  key->qP)) != CRYPT_OK)                { goto errkey; } /* qP = 1/q mod p */
+
+   if ((err = mp_copy( p,  key->p)) != CRYPT_OK)                       { goto errkey; }
+   if ((err = mp_copy( q,  key->q)) != CRYPT_OK)                       { goto errkey; }
+
+   /* set key type (in this case it's CRT optimized) */
+   key->type = PK_PRIVATE;
+
+   /* return ok and free temps */
+   err       = CRYPT_OK;
+   goto cleanup;
+errkey:
+   mp_clear_multi(key->d, key->e, key->N, key->dQ, key->dP, key->qP, key->p, key->q, NULL);
+cleanup:
+   mp_clear_multi(tmp3, tmp2, tmp1, p, q, NULL);
+   return err;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_make_key.c,v $ */
+/* $Revision: 1.14 $ */
+/* $Date: 2006/12/04 22:23:27 $ */