Use carryless multiplies for NIST b233 and k233 curves (GH #783, PR #784)

Use carryless multiplies for NIST b233 and k233 curves.

1 files changed, 18 insertions, 1 deletions

diff --git a/gf2n.h b/gf2n.h
index 4bb34b19..94f2c010 100644
--- a/gf2n.h
+++ b/gf2n.h
@@ -246,6 +246,7 @@ public:
 

 private:

 	friend class GF2NT;

+	friend class GF2NT233;

 

 	SecWordBlock reg;

 };

@@ -344,13 +345,29 @@ public:
 

 	const Element& MultiplicativeInverse(const Element &a) const;

 

-private:

+protected:

 	const Element& Reduced(const Element &a) const;

 

 	unsigned int t0, t1;

 	mutable PolynomialMod2 result;

 };

 

+/// \brief GF(2^n) for b233 and k233

+/// \details GF2NT233 is a specialization of GF2NT that provides Multiply()

+///   and Square() operations when carryless multiplies is available.

+class CRYPTOPP_DLL GF2NT233 : public GF2NT

+{

+public:

+	// polynomial modulus = x^t0 + x^t1 + x^t2, t0 > t1 > t2

+	GF2NT233(unsigned int t0, unsigned int t1, unsigned int t2);

+

+	GF2NP * Clone() const {return new GF2NT233(*this);}

+

+	const Element& Multiply(const Element &a, const Element &b) const;

+

+	const Element& Square(const Element &a) const;

+};

+

 /// \brief GF(2^n) with Pentanomial Basis

 class CRYPTOPP_DLL GF2NPP : public GF2NP

 {