pub/rsa-recover.c: Take out explicit factoring-retry loop.

We have the `again' label anyway, because we need to retry from the
nested square-root-finding loop, and the hope is that we do the thing
once and it works, retrying on failure, rather than iterating over a
thing, so I think I prefer the `goto' here.

diff --git a/pub/rsa-recover.c b/pub/rsa-recover.c
index c09ca4a473935ead32d106d66d64450c1754b957..1e632313f89cee2bf0164c373e459b1c9f0bb22e 100644 (file)
--- a/pub/rsa-recover.c
+++ b/pub/rsa-recover.c
@@ -111,43 +111,42 @@ int rsa_recover(rsa_priv *rp)
 
       mp_build(&a, &aw, &aw + 1);
       i = 0;
 
       mp_build(&a, &aw, &aw + 1);
       i = 0;

+
+    again:
+
+      /* --- Choose a random %$a$% and calculate %$z = a^t \bmod n$% --- *
+       *
+       * If %$z \equiv 1$% or %$z \equiv -1 \pmod n$% then this iteration
+       * is a failure.
+       */
+
+      aw = primetab[i++];
+      z = mpmont_mul(&mm, z, &a, mm.r2);
+      z = mpmont_expr(&mm, z, z, t);
+      if (MP_EQ(z, mm.r) || MP_EQ(z, m1))
+       goto again;
+
+      /* --- Now square until something interesting happens --- *
+       *
+       * Compute %$z^{2i} \bmod n$%.  Eventually, I'll either get %$-1$% or
+       * %$1$%.  If the former, the number is uninteresting, and I need to
+       * restart.  If the latter, the previous number minus 1 has a common
+       * factor with %$n$%.
+       */
+

       for (;;) {
       for (;;) {

-      again:
-
-       /* --- Choose a random %$a$% and calculate %$z = a^t \bmod n$% --- *
-        *
-        * If %$z \equiv 1$% or %$z \equiv -1 \pmod n$% then this iteration
-        * is a failure.
-        */
-
-       aw = primetab[i++];
-       z = mpmont_mul(&mm, z, &a, mm.r2);
-       z = mpmont_expr(&mm, z, z, t);
-       if (MP_EQ(z, mm.r) || MP_EQ(z, m1))
-         continue;
-
-       /* --- Now square until something interesting happens --- *
-        *
-        * Compute %$z^{2i} \bmod n$%.  Eventually, I'll either get %$-1$% or
-        * %$1$%.  If the former, the number is uninteresting, and I need to
-        * restart.  If the latter, the previous number minus 1 has a common
-        * factor with %$n$%.
-        */
-
-       for (;;) {
-         zz = mp_sqr(zz, z);
-         zz = mpmont_reduce(&mm, zz, zz);
-         if (MP_EQ(zz, mm.r)) {
-           mp_drop(zz);
-           goto done;
-         } else if (MP_EQ(zz, m1)) {
-           mp_drop(zz);
-           goto again;
-         }
-         mp_drop(z);
-         z = zz;
-         zz = MP_NEW;
+       zz = mp_sqr(zz, z);
+       zz = mpmont_reduce(&mm, zz, zz);
+       if (MP_EQ(zz, mm.r)) {
+         mp_drop(zz);
+         goto done;
+       } else if (MP_EQ(zz, m1)) {
+         mp_drop(zz);
+         goto again;

        }
        }

+       mp_drop(z);
+       z = zz;
+       zz = MP_NEW;

       }
 
       /* --- Do the factoring --- *
       }
 
       /* --- Do the factoring --- *