Add specialized reducers for P-192, P-224, P-256 and P-384

1 files changed, 24 insertions, 7 deletions

diff --git a/src/lib/math/ec_gfp/curve_gfp.cpp b/src/lib/math/ec_gfp/curve_gfp.cpp
index 02265b53a..cb21dd04e 100644
--- a/src/lib/math/ec_gfp/curve_gfp.cpp
+++ b/src/lib/math/ec_gfp/curve_gfp.cpp
@@ -8,6 +8,7 @@
 #include <botan/curve_gfp.h>
 #include <botan/internal/curve_nistp.h>
 #include <botan/internal/mp_core.h>
+#include <botan/internal/mp_asmi.h>
 
 namespace Botan {
 
@@ -117,25 +118,30 @@ void CurveGFp_Montgomery::curve_sqr(BigInt& z, const BigInt& x,
 }
 
 // Default implementation
-void CurveGFp_Repr::normalize(BigInt& x, secure_vector<word>& ws, size_t /*bound*/) const
+void CurveGFp_Repr::normalize(BigInt& x, secure_vector<word>& ws, size_t bound) const
    {
    const BigInt& p = get_p();
+   const word* prime = p.data();
+   const size_t p_words = get_p_words();
 
    while(x.is_negative())
       x += p;
 
-   const size_t p_words = get_p_words();
-   const word* prime = p.data();
-
    x.grow_to(p_words + 1);
 
    if(ws.size() < p_words + 1)
       ws.resize(p_words + 1);
 
-   //FIXME: take into account bound if > 0
-   while(true)
+   for(size_t i = 0; bound == 0 || i < bound; ++i)
       {
-      if(bigint_sub3(&ws[0], x.data(), p_words, prime, p_words)) // borrow?
+      const word* xd = x.data();
+      word borrow = 0;
+
+      for(size_t i = 0; i != p_words; ++i)
+         ws[i] = word_sub(xd[i], prime[i], &borrow);
+      ws[p_words] = word_sub(xd[p_words], 0, &borrow);
+
+      if(borrow)
          break;
 
       x.swap_reg(ws);
@@ -145,6 +151,17 @@ void CurveGFp_Repr::normalize(BigInt& x, secure_vector<word>& ws, size_t /*bound
 std::shared_ptr<CurveGFp_Repr>
 CurveGFp::choose_repr(const BigInt& p, const BigInt& a, const BigInt& b)
    {
+#if defined(BOTAN_HAS_CURVEGFP_NISTP_M32)
+   if(p == CurveGFp_P192::prime())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P192(a, b));
+   if(p == CurveGFp_P224::prime())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P224(a, b));
+   if(p == CurveGFp_P256::prime())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P256(a, b));
+   if(p == CurveGFp_P384::prime())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P384(a, b));
+#endif
+
    if(p == CurveGFp_P521::prime())
       return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P521(a, b));