1 files changed, 287 insertions, 0 deletions
diff --git a/src/lib/pubkey/ec_group/curve_gfp.cpp b/src/lib/pubkey/ec_group/curve_gfp.cpp
new file mode 100644
index 000000000..83d1c841c
--- /dev/null
+++ b/src/lib/pubkey/ec_group/curve_gfp.cpp
@@ -0,0 +1,287 @@
+/*
+* Elliptic curves over GF(p) Montgomery Representation
+* (C) 2014,2015 Jack Lloyd
+*     2016 Matthias Gierlings
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/curve_gfp.h>
+#include <botan/curve_nistp.h>
+#include <botan/numthry.h>
+#include <botan/internal/mp_core.h>
+#include <botan/internal/mp_asmi.h>
+
+namespace Botan {
+
+namespace {
+
+class CurveGFp_Montgomery final : public CurveGFp_Repr
+   {
+   public:
+      CurveGFp_Montgomery(const BigInt& p, const BigInt& a, const BigInt& b) :
+         m_p(p), m_a(a), m_b(b),
+         m_p_words(m_p.sig_words()),
+         m_p_dash(monty_inverse(m_p.word_at(0)))
+         {
+         const BigInt r = BigInt::power_of_2(m_p_words * BOTAN_MP_WORD_BITS);
+
+         m_r2  = (r * r) % p;
+         m_a_r = (m_a * r) % p;
+         m_b_r = (m_b * r) % p;
+         }
+
+      const BigInt& get_a() const override { return m_a; }
+
+      const BigInt& get_b() const override { return m_b; }
+
+      const BigInt& get_p() const override { return m_p; }
+
+      const BigInt& get_a_rep() const override { return m_a_r; }
+
+      const BigInt& get_b_rep() const override { return m_b_r; }
+
+      size_t get_p_words() const override { return m_p_words; }
+
+      void to_curve_rep(BigInt& x, secure_vector<word>& ws) const override;
+
+      void from_curve_rep(BigInt& x, secure_vector<word>& ws) const override;
+
+      void curve_mul(BigInt& z, const BigInt& x, const BigInt& y,
+                     secure_vector<word>& ws) const override;
+
+      void curve_sqr(BigInt& z, const BigInt& x,
+                     secure_vector<word>& ws) const override;
+   private:
+      BigInt m_p, m_a, m_b;
+      size_t m_p_words; // cache of m_p.sig_words()
+
+      // Montgomery parameters
+      BigInt m_r2, m_a_r, m_b_r;
+      word m_p_dash;
+   };
+
+void CurveGFp_Montgomery::to_curve_rep(BigInt& x, secure_vector<word>& ws) const
+   {
+   const BigInt tx = x;
+   curve_mul(x, tx, m_r2, ws);
+   }
+
+void CurveGFp_Montgomery::from_curve_rep(BigInt& x, secure_vector<word>& ws) const
+   {
+   const BigInt tx = x;
+   curve_mul(x, tx, 1, ws);
+   }
+
+void CurveGFp_Montgomery::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 output_size = 2*m_p_words + 1;
+   ws.resize(2*(m_p_words+2));
+
+   z.grow_to(output_size);
+   z.clear();
+
+   bigint_monty_mul(z, x, y,
+                    m_p.data(), m_p_words, m_p_dash,
+                    ws.data(), ws.size());
+   }
+
+void CurveGFp_Montgomery::curve_sqr(BigInt& z, const BigInt& x,
+                                    secure_vector<word>& ws) const
+   {
+   if(x.is_zero())
+      {
+      z = 0;
+      return;
+      }
+
+   const size_t x_sw = x.sig_words();
+   BOTAN_ASSERT(x_sw <= m_p_words, "Input in range");
+
+   const size_t output_size = 2*m_p_words + 1;
+
+   ws.resize(2*(m_p_words+2));
+
+   z.grow_to(output_size);
+   z.clear();
+
+   bigint_monty_sqr(z, x, m_p.data(), m_p_words, m_p_dash,
+                    ws.data(), ws.size());
+   }
+
+class CurveGFp_NIST : public CurveGFp_Repr
+   {
+   public:
+      CurveGFp_NIST(size_t p_bits, const BigInt& a, const BigInt& b) :
+         m_a(a), m_b(b), m_p_words((p_bits + BOTAN_MP_WORD_BITS - 1) / BOTAN_MP_WORD_BITS)
+         {
+         }
+
+      const BigInt& get_a() const override { return m_a; }
+
+      const BigInt& get_b() const override { return m_b; }
+
+      size_t get_p_words() const override { return m_p_words; }
+
+      const BigInt& get_a_rep() const override { return m_a; }
+
+      const BigInt& get_b_rep() const override { return m_b; }
+
+      void to_curve_rep(BigInt& x, secure_vector<word>& ws) const override
+         { redc(x, ws); }
+
+      void from_curve_rep(BigInt& x, secure_vector<word>& ws) const override
+         { redc(x, ws); }
+
+      void curve_mul(BigInt& z, const BigInt& x, const BigInt& y,
+                     secure_vector<word>& ws) const override;
+
+      void curve_sqr(BigInt& z, const BigInt& x,
+                     secure_vector<word>& ws) const override;
+   private:
+      virtual void redc(BigInt& x, secure_vector<word>& ws) const = 0;
+
+      // Curve parameters
+      BigInt m_a, m_b;
+      size_t m_p_words; // cache of m_p.sig_words()
+   };
+
+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, x, y, ws.data(), ws.size());
+
+   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,
+              x.data(), x.size(), x.sig_words(),
+              ws.data(), ws.size());
+
+   this->redc(z, ws);
+   }
+
+#if defined(BOTAN_HAS_NIST_PRIME_REDUCERS_W32)
+
+/**
+* The NIST P-192 curve
+*/
+class CurveGFp_P192 final : public CurveGFp_NIST
+   {
+   public:
+      CurveGFp_P192(const BigInt& a, const BigInt& b) : CurveGFp_NIST(192, a, b) {}
+      const BigInt& get_p() const override { return prime_p192(); }
+   private:
+      void redc(BigInt& x, secure_vector<word>& ws) const override { redc_p192(x, ws); }
+   };
+
+/**
+* The NIST P-224 curve
+*/
+class CurveGFp_P224 final : public CurveGFp_NIST
+   {
+   public:
+      CurveGFp_P224(const BigInt& a, const BigInt& b) : CurveGFp_NIST(224, a, b) {}
+      const BigInt& get_p() const override { return prime_p224(); }
+   private:
+      void redc(BigInt& x, secure_vector<word>& ws) const override { redc_p224(x, ws); }
+   };
+
+/**
+* The NIST P-256 curve
+*/
+class CurveGFp_P256 final : public CurveGFp_NIST
+   {
+   public:
+      CurveGFp_P256(const BigInt& a, const BigInt& b) : CurveGFp_NIST(256, a, b) {}
+      const BigInt& get_p() const override { return prime_p256(); }
+   private:
+      void redc(BigInt& x, secure_vector<word>& ws) const override { redc_p256(x, ws); }
+   };
+
+/**
+* The NIST P-384 curve
+*/
+class CurveGFp_P384 final : public CurveGFp_NIST
+   {
+   public:
+      CurveGFp_P384(const BigInt& a, const BigInt& b) : CurveGFp_NIST(384, a, b) {}
+      const BigInt& get_p() const override { return prime_p384(); }
+   private:
+      void redc(BigInt& x, secure_vector<word>& ws) const override { redc_p384(x, ws); }
+   };
+
+#endif
+
+/**
+* The NIST P-521 curve
+*/
+class CurveGFp_P521 final : public CurveGFp_NIST
+   {
+   public:
+      CurveGFp_P521(const BigInt& a, const BigInt& b) : CurveGFp_NIST(521, a, b) {}
+      const BigInt& get_p() const override { return prime_p521(); }
+   private:
+      void redc(BigInt& x, secure_vector<word>& ws) const override { redc_p521(x, ws); }
+   };
+
+}
+
+std::shared_ptr<CurveGFp_Repr>
+CurveGFp::choose_repr(const BigInt& p, const BigInt& a, const BigInt& b)
+   {
+#if defined(BOTAN_HAS_NIST_PRIME_REDUCERS_W32)
+   if(p == prime_p192())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P192(a, b));
+   if(p == prime_p224())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P224(a, b));
+   if(p == prime_p256())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P256(a, b));
+   if(p == prime_p384())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P384(a, b));
+#endif
+
+   if(p == prime_p521())
+      return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_P521(a, b));
+
+   return std::shared_ptr<CurveGFp_Repr>(new CurveGFp_Montgomery(p, a, b));
+   }
+
+}