1 files changed, 95 insertions, 0 deletions
diff --git a/src/lib/math/ec_gfp/curve_nistp.cpp b/src/lib/math/ec_gfp/curve_nistp.cpp
new file mode 100644
index 000000000..1aac01f56
--- /dev/null
+++ b/src/lib/math/ec_gfp/curve_nistp.cpp
@@ -0,0 +1,95 @@
+/*
+* NIST curve reduction
+* (C) 2014 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/internal/curve_nistp.h>
+#include <botan/internal/mp_core.h>
+#include <botan/internal/rounding.h>
+#include <botan/hex.h>
+
+namespace Botan {
+
+void CurveGFp_NIST::curve_mul(BigInt& z, const BigInt& x, const BigInt& y,
+                              secure_vector<word>& ws) const
+   {
+   if(x.is_zero() || y.is_zero())
+      {
+      z = 0;
+      return;
+      }
+
+   const size_t p_words = get_p_words();
+   const size_t output_size = 2*p_words + 1;
+   ws.resize(2*(p_words+2));
+
+   z.grow_to(output_size);
+   z.clear();
+
+   bigint_mul(z.mutable_data(), output_size, &ws[0],
+              x.data(), x.size(), x.sig_words(),
+              y.data(), y.size(), y.sig_words());
+
+   this->redc(z, ws);
+   }
+
+void CurveGFp_NIST::curve_sqr(BigInt& z, const BigInt& x,
+                              secure_vector<word>& ws) const
+   {
+   if(x.is_zero())
+      {
+      z = 0;
+      return;
+      }
+
+   const size_t p_words = get_p_words();
+   const size_t output_size = 2*p_words + 1;
+
+   ws.resize(2*(p_words+2));
+
+   z.grow_to(output_size);
+   z.clear();
+
+   bigint_sqr(z.mutable_data(), output_size, &ws[0],
+              x.data(), x.size(), x.sig_words());
+
+   this->redc(z, ws);
+   }
+
+//static
+const BigInt& CurveGFp_P521::prime()
+   {
+   static const BigInt p521("0x1FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"
+                               "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF");
+
+   return p521;
+   }
+
+void CurveGFp_P521::redc(BigInt& x, secure_vector<word>& ws) const
+   {
+   const size_t p_words = get_p_words();
+
+   const size_t shift_words = 521 / MP_WORD_BITS,
+                shift_bits  = 521 % MP_WORD_BITS;
+
+   const size_t x_sw = x.sig_words();
+
+   if(x_sw < p_words)
+      return; // already smaller
+
+   if(ws.size() < p_words + 1)
+      ws.resize(p_words + 1);
+
+   clear_mem(&ws[0], ws.size());
+   bigint_shr2(&ws[0], x.data(), x_sw, shift_words, shift_bits);
+
+   x.mask_bits(521);
+
+   bigint_add3(x.mutable_data(), x.data(), p_words, &ws[0], p_words);
+
+   normalize(x, ws, max_redc_subtractions());
+   }
+
+}