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Diffstat (limited to 'plugins/CryptoPP/crypto/xtr.h')
| -rw-r--r-- | plugins/CryptoPP/crypto/xtr.h | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/plugins/CryptoPP/crypto/xtr.h b/plugins/CryptoPP/crypto/xtr.h new file mode 100644 index 0000000000..40ca8a14ab --- /dev/null +++ b/plugins/CryptoPP/crypto/xtr.h @@ -0,0 +1,215 @@ +#ifndef CRYPTOPP_XTR_H
+#define CRYPTOPP_XTR_H
+
+/** \file
+ "The XTR public key system" by Arjen K. Lenstra and Eric R. Verheul
+*/
+
+#include "modarith.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+//! an element of GF(p^2)
+class GFP2Element
+{
+public:
+ GFP2Element() {}
+ GFP2Element(const Integer &c1, const Integer &c2) : c1(c1), c2(c2) {}
+ GFP2Element(const byte *encodedElement, unsigned int size)
+ : c1(encodedElement, size/2), c2(encodedElement+size/2, size/2) {}
+
+ void Encode(byte *encodedElement, unsigned int size)
+ {
+ c1.Encode(encodedElement, size/2);
+ c2.Encode(encodedElement+size/2, size/2);
+ }
+
+ bool operator==(const GFP2Element &rhs) const {return c1 == rhs.c1 && c2 == rhs.c2;}
+ bool operator!=(const GFP2Element &rhs) const {return !operator==(rhs);}
+
+ void swap(GFP2Element &a)
+ {
+ c1.swap(a.c1);
+ c2.swap(a.c2);
+ }
+
+ static const GFP2Element & Zero();
+
+ Integer c1, c2;
+};
+
+//! GF(p^2), optimal normal basis
+template <class F>
+class GFP2_ONB : public AbstractRing<GFP2Element>
+{
+public:
+ typedef F BaseField;
+
+ GFP2_ONB(const Integer &p) : modp(p)
+ {
+ if (p%3 != 2)
+ throw InvalidArgument("GFP2_ONB: modulus must be equivalent to 2 mod 3");
+ }
+
+ const Integer& GetModulus() const {return modp.GetModulus();}
+
+ GFP2Element ConvertIn(const Integer &a) const
+ {
+ t = modp.Inverse(modp.ConvertIn(a));
+ return GFP2Element(t, t);
+ }
+
+ GFP2Element ConvertIn(const GFP2Element &a) const
+ {return GFP2Element(modp.ConvertIn(a.c1), modp.ConvertIn(a.c2));}
+
+ GFP2Element ConvertOut(const GFP2Element &a) const
+ {return GFP2Element(modp.ConvertOut(a.c1), modp.ConvertOut(a.c2));}
+
+ bool Equal(const GFP2Element &a, const GFP2Element &b) const
+ {
+ return modp.Equal(a.c1, b.c1) && modp.Equal(a.c2, b.c2);
+ }
+
+ const Element& Identity() const
+ {
+ return GFP2Element::Zero();
+ }
+
+ const Element& Add(const Element &a, const Element &b) const
+ {
+ result.c1 = modp.Add(a.c1, b.c1);
+ result.c2 = modp.Add(a.c2, b.c2);
+ return result;
+ }
+
+ const Element& Inverse(const Element &a) const
+ {
+ result.c1 = modp.Inverse(a.c1);
+ result.c2 = modp.Inverse(a.c2);
+ return result;
+ }
+
+ const Element& Double(const Element &a) const
+ {
+ result.c1 = modp.Double(a.c1);
+ result.c2 = modp.Double(a.c2);
+ return result;
+ }
+
+ const Element& Subtract(const Element &a, const Element &b) const
+ {
+ result.c1 = modp.Subtract(a.c1, b.c1);
+ result.c2 = modp.Subtract(a.c2, b.c2);
+ return result;
+ }
+
+ Element& Accumulate(Element &a, const Element &b) const
+ {
+ modp.Accumulate(a.c1, b.c1);
+ modp.Accumulate(a.c2, b.c2);
+ return a;
+ }
+
+ Element& Reduce(Element &a, const Element &b) const
+ {
+ modp.Reduce(a.c1, b.c1);
+ modp.Reduce(a.c2, b.c2);
+ return a;
+ }
+
+ bool IsUnit(const Element &a) const
+ {
+ return a.c1.NotZero() || a.c2.NotZero();
+ }
+
+ const Element& MultiplicativeIdentity() const
+ {
+ result.c1 = result.c2 = modp.Inverse(modp.MultiplicativeIdentity());
+ return result;
+ }
+
+ const Element& Multiply(const Element &a, const Element &b) const
+ {
+ t = modp.Add(a.c1, a.c2);
+ t = modp.Multiply(t, modp.Add(b.c1, b.c2));
+ result.c1 = modp.Multiply(a.c1, b.c1);
+ result.c2 = modp.Multiply(a.c2, b.c2);
+ result.c1.swap(result.c2);
+ modp.Reduce(t, result.c1);
+ modp.Reduce(t, result.c2);
+ modp.Reduce(result.c1, t);
+ modp.Reduce(result.c2, t);
+ return result;
+ }
+
+ const Element& MultiplicativeInverse(const Element &a) const
+ {
+ return result = Exponentiate(a, modp.GetModulus()-2);
+ }
+
+ const Element& Square(const Element &a) const
+ {
+ const Integer &ac1 = (&a == &result) ? (t = a.c1) : a.c1;
+ result.c1 = modp.Multiply(modp.Subtract(modp.Subtract(a.c2, a.c1), a.c1), a.c2);
+ result.c2 = modp.Multiply(modp.Subtract(modp.Subtract(ac1, a.c2), a.c2), ac1);
+ return result;
+ }
+
+ Element Exponentiate(const Element &a, const Integer &e) const
+ {
+ Integer edivp, emodp;
+ Integer::Divide(emodp, edivp, e, modp.GetModulus());
+ Element b = PthPower(a);
+ return AbstractRing<GFP2Element>::CascadeExponentiate(a, emodp, b, edivp);
+ }
+
+ const Element & PthPower(const Element &a) const
+ {
+ result = a;
+ result.c1.swap(result.c2);
+ return result;
+ }
+
+ void RaiseToPthPower(Element &a) const
+ {
+ a.c1.swap(a.c2);
+ }
+
+ // a^2 - 2a^p
+ const Element & SpecialOperation1(const Element &a) const
+ {
+ assert(&a != &result);
+ result = Square(a);
+ modp.Reduce(result.c1, a.c2);
+ modp.Reduce(result.c1, a.c2);
+ modp.Reduce(result.c2, a.c1);
+ modp.Reduce(result.c2, a.c1);
+ return result;
+ }
+
+ // x * z - y * z^p
+ const Element & SpecialOperation2(const Element &x, const Element &y, const Element &z) const
+ {
+ assert(&x != &result && &y != &result && &z != &result);
+ t = modp.Add(x.c2, y.c2);
+ result.c1 = modp.Multiply(z.c1, modp.Subtract(y.c1, t));
+ modp.Accumulate(result.c1, modp.Multiply(z.c2, modp.Subtract(t, x.c1)));
+ t = modp.Add(x.c1, y.c1);
+ result.c2 = modp.Multiply(z.c2, modp.Subtract(y.c2, t));
+ modp.Accumulate(result.c2, modp.Multiply(z.c1, modp.Subtract(t, x.c2)));
+ return result;
+ }
+
+protected:
+ BaseField modp;
+ mutable GFP2Element result;
+ mutable Integer t;
+};
+
+void XTR_FindPrimesAndGenerator(RandomNumberGenerator &rng, Integer &p, Integer &q, GFP2Element &g, unsigned int pbits, unsigned int qbits);
+
+GFP2Element XTR_Exponentiate(const GFP2Element &b, const Integer &e, const Integer &p);
+
+NAMESPACE_END
+
+#endif
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