X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a..141c12847a1c2f8cc8db03d420551584e689fb87:/pub/rsa-pub.c

diff --git a/pub/rsa-pub.c b/pub/rsa-pub.c
index 78793a92..bb402a3a 100644
--- a/pub/rsa-pub.c
+++ b/pub/rsa-pub.c
@@ -29,6 +29,7 @@
 #include <mLib/alloc.h>
 #include <mLib/bits.h>
 #include <mLib/dstr.h>
+#include <mLib/macros.h>
 
 #include "mp.h"
 #include "mpmont.h"
@@ -48,7 +49,7 @@
 
 void rsa_pubcreate(rsa_pubctx *rd, rsa_pub *rp)
 {
-  rd->rp = rp;
+  rd->rp = rp; mp_shrink(rp->e);
   mpmont_create(&rd->mm, rp->n);
 }
 
@@ -79,6 +80,31 @@ void rsa_pubdestroy(rsa_pubctx *rd)
 
 mp *rsa_pubop(rsa_pubctx *rd, mp *d, mp *p)
 {
+  mp *e = rd->rp->e;
+  unsigned i;
+
+  if (MP_EQ(e, MP_THREE)) {
+    MP_COPY(p);
+    d = mpmont_mul(&rd->mm, d, p, rd->mm.r2);
+    d = mp_sqr(d, d); d = mpmont_reduce(&rd->mm, d, d);
+    d = mpmont_mul(&rd->mm, d, d, p);
+    MP_DROP(p);
+    return (d);
+  }
+#if MPW_BITS > 16
+  if (MP_LEN(e) == 1 && e->v[0] == 65537)
+#else
+  if (0 && MP_LEN(e) == 2 && e->v[0] == 1 && e->v[1] == (1 << (16 - MPW_BITS)))
+#endif
+  {
+    MP_COPY(p);
+    d = mpmont_mul(&rd->mm, d, p, rd->mm.r2);
+    for (i = 0; i < 16; i++)
+      { d = mp_sqr(d, d); d = mpmont_reduce(&rd->mm, d, d); }
+    d = mpmont_mul(&rd->mm, d, d, p);
+    MP_DROP(p);
+    return (d);
+  }
   return (mpmont_exp(&rd->mm, d, p, rd->rp->e));
 }
 
@@ -175,7 +201,7 @@ int rsa_verify(rsa_pubctx *rp, mp *s, const void *m, size_t msz,
   dstr_ensure(d, n);
   rc = e(p, m, msz, (octet *)d->buf + d->len, n, nb, earg);
   if (rc > 0 && m) {
-    if (rc != msz || memcmp(d->buf + d->len, m, msz) != 0)
+    if (rc != msz || MEMCMP(d->buf + d->len, !=, m, msz))
       rc = -1;
     else
       rc = 0;