--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/katja/katja_make_key.c	Sat Feb 03 08:20:30 2007 +0000
@@ -0,0 +1,101 @@
+/* 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, [email protected], http://libtomcrypt.com
+ */
+#include "tomcrypt.h"
+
+/**
+  @file katja_make_key.c
+  Katja key generation, Tom St Denis
+*/  
+
+#ifdef MKAT
+
+/** 
+   Create a Katja 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 key      [out] Destination of a newly created private key pair
+   @return CRYPT_OK if successful, upon error all allocated ram is freed
+*/
+int katja_make_key(prng_state *prng, int wprng, int size, katja_key *key)
+{
+   void *p, *q, *tmp1, *tmp2;
+   int    err;
+  
+   LTC_ARGCHK(key != NULL);
+   LTC_ARGCHK(ltc_mp.name != NULL);
+
+   if ((size < (MIN_KAT_SIZE/8)) || (size > (MAX_KAT_SIZE/8))) {
+      return CRYPT_INVALID_KEYSIZE;
+   }
+
+   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((err = mp_init_multi(&p, &q, &tmp1, &tmp2, NULL)) != CRYPT_OK) {
+      return err;
+   }
+
+   /* divide size by three  */
+   size   = (((size << 3) / 3) + 7) >> 3;
+
+   /* make prime "q" (we negate size to make q == 3 mod 4) */
+   if ((err = rand_prime(q, -size, prng, wprng)) != CRYPT_OK)      { goto done; }
+   if ((err = mp_sub_d(q, 1, tmp1)) != CRYPT_OK)                   { goto done; }
+
+   /* make prime "p" */
+   do {
+      if ((err = rand_prime(p, size+1, prng, wprng)) != CRYPT_OK)  { goto done; }
+      if ((err = mp_gcd(p, tmp1, tmp2)) != CRYPT_OK)               { goto done; }
+   } while (mp_cmp_d(tmp2, 1) != LTC_MP_EQ);
+
+   /* make key */
+   if ((err = mp_init_multi(&key->d, &key->N, &key->dQ, &key->dP,
+                     &key->qP, &key->p, &key->q, &key->pq, NULL)) != CRYPT_OK) {
+      goto error;
+   }
+
+   /* n=p^2q and 1/n mod pq */
+   if ((err = mp_copy( p,  key->p)) != CRYPT_OK)                       { goto error2; }
+   if ((err = mp_copy( q,  key->q)) != CRYPT_OK)                       { goto error2; }
+   if ((err = mp_mul(key->p, key->q, key->pq)) != CRYPT_OK)            { goto error2; } /* tmp1 = pq  */
+   if ((err = mp_mul(key->pq, key->p, key->N)) != CRYPT_OK)            { goto error2; } /* N = p^2q   */  
+   if ((err = mp_sub_d( p, 1,  tmp1)) != CRYPT_OK)                     { goto error2; } /* tmp1 = q-1 */
+   if ((err = mp_sub_d( q, 1,  tmp2)) != CRYPT_OK)                     { goto error2; } /* tmp2 = p-1 */
+   if ((err = mp_lcm(tmp1, tmp2, key->d)) != CRYPT_OK)                 { goto error2; } /* tmp1 = lcd(p-1,q-1) */
+   if ((err = mp_invmod( key->N,  key->d,  key->d)) != CRYPT_OK)       { goto error2; } /* key->d = 1/N mod pq */
+
+   /* optimize for CRT now */
+   /* find d mod q-1 and d mod p-1 */
+   if ((err = mp_mod( key->d,  tmp1,  key->dP)) != CRYPT_OK)           { goto error2; } /* dP = d mod p-1 */
+   if ((err = mp_mod( key->d,  tmp2,  key->dQ)) != CRYPT_OK)           { goto error2; } /* dQ = d mod q-1 */
+   if ((err = mp_invmod( q,  p,  key->qP)) != CRYPT_OK)                { goto error2; } /* qP = 1/q mod p */
+
+   /* set key type (in this case it's CRT optimized) */
+   key->type = PK_PRIVATE;
+
+   /* return ok and free temps */
+   err       = CRYPT_OK;
+   goto done;
+error2:
+   mp_clear_multi( key->d,  key->N,  key->dQ,  key->dP,  key->qP,  key->p,  key->q, key->pq, NULL);
+error:
+done:
+   mp_clear_multi( tmp2,  tmp1,  p,  q, NULL);
+   return err;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/pk/katja/katja_make_key.c,v $ */
+/* $Revision: 1.10 $ */
+/* $Date: 2006/03/31 14:15:35 $ */