--- a/rsa_exptmod.c	Mon May 31 18:25:41 2004 +0000
+++ b/rsa_exptmod.c	Tue Jun 15 14:07:21 2004 +0000
@@ -14,18 +14,23 @@
 
 #ifdef MRSA
 
-int rsa_exptmod(const unsigned char *in,  unsigned long inlen,
-                      unsigned char *out, unsigned long *outlen, int which,
+int rsa_exptmod(const unsigned char *in,   unsigned long inlen,
+                      unsigned char *out,  unsigned long *outlen, int which,
+                      prng_state    *prng, int           prng_idx,
                       rsa_key *key)
 {
-   mp_int tmp, tmpa, tmpb;
+   mp_int        tmp, tmpa, tmpb;
    unsigned long x;
-   int err;
+   int           err;
 
    _ARGCHK(in     != NULL);
    _ARGCHK(out    != NULL);
    _ARGCHK(outlen != NULL);
    _ARGCHK(key    != NULL);
+   
+   if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
+      return err;
+   }
 
    if (which == PK_PRIVATE && (key->type != PK_PRIVATE && key->type != PK_PRIVATE_OPTIMIZED)) {
       return CRYPT_PK_NOT_PRIVATE;
@@ -49,10 +54,10 @@
    /* are we using the private exponent and is the key optimized? */
    if (which == PK_PRIVATE && key->type == PK_PRIVATE_OPTIMIZED) {
       /* tmpa = tmp^dP mod p */
-      if ((err = mp_exptmod(&tmp, &key->dP, &key->p, &tmpa)) != MP_OKAY)    { goto error; }
+      if ((err = tim_exptmod(prng, prng_idx, &tmp, &key->e, &key->dP, &key->p, &tmpa)) != MP_OKAY)    { goto error; }
 
       /* tmpb = tmp^dQ mod q */
-      if ((err = mp_exptmod(&tmp, &key->dQ, &key->q, &tmpb)) != MP_OKAY)    { goto error; }
+      if ((err = tim_exptmod(prng, prng_idx, &tmp, &key->e,  &key->dQ, &key->q, &tmpb)) != MP_OKAY)    { goto error; }
 
       /* tmp = tmpa*qP + tmpb*pQ mod N */
       if ((err = mp_mul(&tmpa, &key->qP, &tmpa)) != MP_OKAY)                { goto error; }
@@ -60,11 +65,15 @@
       if ((err = mp_addmod(&tmpa, &tmpb, &key->N, &tmp)) != MP_OKAY)        { goto error; }
    } else {
       /* exptmod it */
-      if ((err = mp_exptmod(&tmp, which==PK_PRIVATE?&key->d:&key->e, &key->N, &tmp)) != MP_OKAY) { goto error; }
+      if (which == PK_PRIVATE) {
+         if ((err = tim_exptmod(prng, prng_idx, &tmp, &key->e, &key->d, &key->N, &tmp)) != MP_OKAY) { goto error; }
+      } else {
+         if ((err = mp_exptmod(&tmp, &key->e, &key->N, &tmp)) != MP_OKAY) { goto error; }
+      }
    }
 
    /* read it back */
-   x = (unsigned long)mp_unsigned_bin_size(&tmp);
+   x = (unsigned long)mp_unsigned_bin_size(&key->N);
    if (x > *outlen) {
       err = CRYPT_BUFFER_OVERFLOW;
       goto done;
@@ -72,7 +81,8 @@
    *outlen = x;
 
    /* convert it */
-   if ((err = mp_to_unsigned_bin(&tmp, out)) != MP_OKAY)                    { goto error; }
+   zeromem(out, x);
+   if ((err = mp_to_unsigned_bin(&tmp, out+(x-mp_unsigned_bin_size(&tmp)))) != MP_OKAY) { goto error; }
 
    /* clean up and return */
    err = CRYPT_OK;