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authorAlexander Harkness <bearbin@gmail.com>2013-11-24 15:21:13 +0100
committerAlexander Harkness <bearbin@gmail.com>2013-11-24 15:21:13 +0100
commit3438e5d3ddf8444f0e31009ffbe8237ef3752c22 (patch)
tree7c2f76d5e9281c130e60fb932c4dda89a49863b6 /CryptoPP/ecp.cpp
parentMoved source to src (diff)
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Diffstat (limited to 'CryptoPP/ecp.cpp')
-rw-r--r--CryptoPP/ecp.cpp473
1 files changed, 0 insertions, 473 deletions
diff --git a/CryptoPP/ecp.cpp b/CryptoPP/ecp.cpp
deleted file mode 100644
index 55a7cc15b..000000000
--- a/CryptoPP/ecp.cpp
+++ /dev/null
@@ -1,473 +0,0 @@
-// ecp.cpp - written and placed in the public domain by Wei Dai
-
-#include "pch.h"
-
-#ifndef CRYPTOPP_IMPORTS
-
-#include "ecp.h"
-#include "asn.h"
-#include "nbtheory.h"
-
-#include "algebra.cpp"
-
-NAMESPACE_BEGIN(CryptoPP)
-
-ANONYMOUS_NAMESPACE_BEGIN
-static inline ECP::Point ToMontgomery(const ModularArithmetic &mr, const ECP::Point &P)
-{
- return P.identity ? P : ECP::Point(mr.ConvertIn(P.x), mr.ConvertIn(P.y));
-}
-
-static inline ECP::Point FromMontgomery(const ModularArithmetic &mr, const ECP::Point &P)
-{
- return P.identity ? P : ECP::Point(mr.ConvertOut(P.x), mr.ConvertOut(P.y));
-}
-NAMESPACE_END
-
-ECP::ECP(const ECP &ecp, bool convertToMontgomeryRepresentation)
-{
- if (convertToMontgomeryRepresentation && !ecp.GetField().IsMontgomeryRepresentation())
- {
- m_fieldPtr.reset(new MontgomeryRepresentation(ecp.GetField().GetModulus()));
- m_a = GetField().ConvertIn(ecp.m_a);
- m_b = GetField().ConvertIn(ecp.m_b);
- }
- else
- operator=(ecp);
-}
-
-ECP::ECP(BufferedTransformation &bt)
- : m_fieldPtr(new Field(bt))
-{
- BERSequenceDecoder seq(bt);
- GetField().BERDecodeElement(seq, m_a);
- GetField().BERDecodeElement(seq, m_b);
- // skip optional seed
- if (!seq.EndReached())
- {
- SecByteBlock seed;
- unsigned int unused;
- BERDecodeBitString(seq, seed, unused);
- }
- seq.MessageEnd();
-}
-
-void ECP::DEREncode(BufferedTransformation &bt) const
-{
- GetField().DEREncode(bt);
- DERSequenceEncoder seq(bt);
- GetField().DEREncodeElement(seq, m_a);
- GetField().DEREncodeElement(seq, m_b);
- seq.MessageEnd();
-}
-
-bool ECP::DecodePoint(ECP::Point &P, const byte *encodedPoint, size_t encodedPointLen) const
-{
- StringStore store(encodedPoint, encodedPointLen);
- return DecodePoint(P, store, encodedPointLen);
-}
-
-bool ECP::DecodePoint(ECP::Point &P, BufferedTransformation &bt, size_t encodedPointLen) const
-{
- byte type;
- if (encodedPointLen < 1 || !bt.Get(type))
- return false;
-
- switch (type)
- {
- case 0:
- P.identity = true;
- return true;
- case 2:
- case 3:
- {
- if (encodedPointLen != EncodedPointSize(true))
- return false;
-
- Integer p = FieldSize();
-
- P.identity = false;
- P.x.Decode(bt, GetField().MaxElementByteLength());
- P.y = ((P.x*P.x+m_a)*P.x+m_b) % p;
-
- if (Jacobi(P.y, p) !=1)
- return false;
-
- P.y = ModularSquareRoot(P.y, p);
-
- if ((type & 1) != P.y.GetBit(0))
- P.y = p-P.y;
-
- return true;
- }
- case 4:
- {
- if (encodedPointLen != EncodedPointSize(false))
- return false;
-
- unsigned int len = GetField().MaxElementByteLength();
- P.identity = false;
- P.x.Decode(bt, len);
- P.y.Decode(bt, len);
- return true;
- }
- default:
- return false;
- }
-}
-
-void ECP::EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const
-{
- if (P.identity)
- NullStore().TransferTo(bt, EncodedPointSize(compressed));
- else if (compressed)
- {
- bt.Put(2 + P.y.GetBit(0));
- P.x.Encode(bt, GetField().MaxElementByteLength());
- }
- else
- {
- unsigned int len = GetField().MaxElementByteLength();
- bt.Put(4); // uncompressed
- P.x.Encode(bt, len);
- P.y.Encode(bt, len);
- }
-}
-
-void ECP::EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const
-{
- ArraySink sink(encodedPoint, EncodedPointSize(compressed));
- EncodePoint(sink, P, compressed);
- assert(sink.TotalPutLength() == EncodedPointSize(compressed));
-}
-
-ECP::Point ECP::BERDecodePoint(BufferedTransformation &bt) const
-{
- SecByteBlock str;
- BERDecodeOctetString(bt, str);
- Point P;
- if (!DecodePoint(P, str, str.size()))
- BERDecodeError();
- return P;
-}
-
-void ECP::DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const
-{
- SecByteBlock str(EncodedPointSize(compressed));
- EncodePoint(str, P, compressed);
- DEREncodeOctetString(bt, str);
-}
-
-bool ECP::ValidateParameters(RandomNumberGenerator &rng, unsigned int level) const
-{
- Integer p = FieldSize();
-
- bool pass = p.IsOdd();
- pass = pass && !m_a.IsNegative() && m_a<p && !m_b.IsNegative() && m_b<p;
-
- if (level >= 1)
- pass = pass && ((4*m_a*m_a*m_a+27*m_b*m_b)%p).IsPositive();
-
- if (level >= 2)
- pass = pass && VerifyPrime(rng, p);
-
- return pass;
-}
-
-bool ECP::VerifyPoint(const Point &P) const
-{
- const FieldElement &x = P.x, &y = P.y;
- Integer p = FieldSize();
- return P.identity ||
- (!x.IsNegative() && x<p && !y.IsNegative() && y<p
- && !(((x*x+m_a)*x+m_b-y*y)%p));
-}
-
-bool ECP::Equal(const Point &P, const Point &Q) const
-{
- if (P.identity && Q.identity)
- return true;
-
- if (P.identity && !Q.identity)
- return false;
-
- if (!P.identity && Q.identity)
- return false;
-
- return (GetField().Equal(P.x,Q.x) && GetField().Equal(P.y,Q.y));
-}
-
-const ECP::Point& ECP::Identity() const
-{
- return Singleton<Point>().Ref();
-}
-
-const ECP::Point& ECP::Inverse(const Point &P) const
-{
- if (P.identity)
- return P;
- else
- {
- m_R.identity = false;
- m_R.x = P.x;
- m_R.y = GetField().Inverse(P.y);
- return m_R;
- }
-}
-
-const ECP::Point& ECP::Add(const Point &P, const Point &Q) const
-{
- if (P.identity) return Q;
- if (Q.identity) return P;
- if (GetField().Equal(P.x, Q.x))
- return GetField().Equal(P.y, Q.y) ? Double(P) : Identity();
-
- FieldElement t = GetField().Subtract(Q.y, P.y);
- t = GetField().Divide(t, GetField().Subtract(Q.x, P.x));
- FieldElement x = GetField().Subtract(GetField().Subtract(GetField().Square(t), P.x), Q.x);
- m_R.y = GetField().Subtract(GetField().Multiply(t, GetField().Subtract(P.x, x)), P.y);
-
- m_R.x.swap(x);
- m_R.identity = false;
- return m_R;
-}
-
-const ECP::Point& ECP::Double(const Point &P) const
-{
- if (P.identity || P.y==GetField().Identity()) return Identity();
-
- FieldElement t = GetField().Square(P.x);
- t = GetField().Add(GetField().Add(GetField().Double(t), t), m_a);
- t = GetField().Divide(t, GetField().Double(P.y));
- FieldElement x = GetField().Subtract(GetField().Subtract(GetField().Square(t), P.x), P.x);
- m_R.y = GetField().Subtract(GetField().Multiply(t, GetField().Subtract(P.x, x)), P.y);
-
- m_R.x.swap(x);
- m_R.identity = false;
- return m_R;
-}
-
-template <class T, class Iterator> void ParallelInvert(const AbstractRing<T> &ring, Iterator begin, Iterator end)
-{
- size_t n = end-begin;
- if (n == 1)
- *begin = ring.MultiplicativeInverse(*begin);
- else if (n > 1)
- {
- std::vector<T> vec((n+1)/2);
- unsigned int i;
- Iterator it;
-
- for (i=0, it=begin; i<n/2; i++, it+=2)
- vec[i] = ring.Multiply(*it, *(it+1));
- if (n%2 == 1)
- vec[n/2] = *it;
-
- ParallelInvert(ring, vec.begin(), vec.end());
-
- for (i=0, it=begin; i<n/2; i++, it+=2)
- {
- if (!vec[i])
- {
- *it = ring.MultiplicativeInverse(*it);
- *(it+1) = ring.MultiplicativeInverse(*(it+1));
- }
- else
- {
- std::swap(*it, *(it+1));
- *it = ring.Multiply(*it, vec[i]);
- *(it+1) = ring.Multiply(*(it+1), vec[i]);
- }
- }
- if (n%2 == 1)
- *it = vec[n/2];
- }
-}
-
-struct ProjectivePoint
-{
- ProjectivePoint() {}
- ProjectivePoint(const Integer &x, const Integer &y, const Integer &z)
- : x(x), y(y), z(z) {}
-
- Integer x,y,z;
-};
-
-class ProjectiveDoubling
-{
-public:
- ProjectiveDoubling(const ModularArithmetic &mr, const Integer &m_a, const Integer &m_b, const ECPPoint &Q)
- : mr(mr), firstDoubling(true), negated(false)
- {
- if (Q.identity)
- {
- sixteenY4 = P.x = P.y = mr.MultiplicativeIdentity();
- aZ4 = P.z = mr.Identity();
- }
- else
- {
- P.x = Q.x;
- P.y = Q.y;
- sixteenY4 = P.z = mr.MultiplicativeIdentity();
- aZ4 = m_a;
- }
- }
-
- void Double()
- {
- twoY = mr.Double(P.y);
- P.z = mr.Multiply(P.z, twoY);
- fourY2 = mr.Square(twoY);
- S = mr.Multiply(fourY2, P.x);
- aZ4 = mr.Multiply(aZ4, sixteenY4);
- M = mr.Square(P.x);
- M = mr.Add(mr.Add(mr.Double(M), M), aZ4);
- P.x = mr.Square(M);
- mr.Reduce(P.x, S);
- mr.Reduce(P.x, S);
- mr.Reduce(S, P.x);
- P.y = mr.Multiply(M, S);
- sixteenY4 = mr.Square(fourY2);
- mr.Reduce(P.y, mr.Half(sixteenY4));
- }
-
- const ModularArithmetic &mr;
- ProjectivePoint P;
- bool firstDoubling, negated;
- Integer sixteenY4, aZ4, twoY, fourY2, S, M;
-};
-
-struct ZIterator
-{
- ZIterator() {}
- ZIterator(std::vector<ProjectivePoint>::iterator it) : it(it) {}
- Integer& operator*() {return it->z;}
- int operator-(ZIterator it2) {return int(it-it2.it);}
- ZIterator operator+(int i) {return ZIterator(it+i);}
- ZIterator& operator+=(int i) {it+=i; return *this;}
- std::vector<ProjectivePoint>::iterator it;
-};
-
-ECP::Point ECP::ScalarMultiply(const Point &P, const Integer &k) const
-{
- Element result;
- if (k.BitCount() <= 5)
- AbstractGroup<ECPPoint>::SimultaneousMultiply(&result, P, &k, 1);
- else
- ECP::SimultaneousMultiply(&result, P, &k, 1);
- return result;
-}
-
-void ECP::SimultaneousMultiply(ECP::Point *results, const ECP::Point &P, const Integer *expBegin, unsigned int expCount) const
-{
- if (!GetField().IsMontgomeryRepresentation())
- {
- ECP ecpmr(*this, true);
- const ModularArithmetic &mr = ecpmr.GetField();
- ecpmr.SimultaneousMultiply(results, ToMontgomery(mr, P), expBegin, expCount);
- for (unsigned int i=0; i<expCount; i++)
- results[i] = FromMontgomery(mr, results[i]);
- return;
- }
-
- ProjectiveDoubling rd(GetField(), m_a, m_b, P);
- std::vector<ProjectivePoint> bases;
- std::vector<WindowSlider> exponents;
- exponents.reserve(expCount);
- std::vector<std::vector<word32> > baseIndices(expCount);
- std::vector<std::vector<bool> > negateBase(expCount);
- std::vector<std::vector<word32> > exponentWindows(expCount);
- unsigned int i;
-
- for (i=0; i<expCount; i++)
- {
- assert(expBegin->NotNegative());
- exponents.push_back(WindowSlider(*expBegin++, InversionIsFast(), 5));
- exponents[i].FindNextWindow();
- }
-
- unsigned int expBitPosition = 0;
- bool notDone = true;
-
- while (notDone)
- {
- notDone = false;
- bool baseAdded = false;
- for (i=0; i<expCount; i++)
- {
- if (!exponents[i].finished && expBitPosition == exponents[i].windowBegin)
- {
- if (!baseAdded)
- {
- bases.push_back(rd.P);
- baseAdded =true;
- }
-
- exponentWindows[i].push_back(exponents[i].expWindow);
- baseIndices[i].push_back((word32)bases.size()-1);
- negateBase[i].push_back(exponents[i].negateNext);
-
- exponents[i].FindNextWindow();
- }
- notDone = notDone || !exponents[i].finished;
- }
-
- if (notDone)
- {
- rd.Double();
- expBitPosition++;
- }
- }
-
- // convert from projective to affine coordinates
- ParallelInvert(GetField(), ZIterator(bases.begin()), ZIterator(bases.end()));
- for (i=0; i<bases.size(); i++)
- {
- if (bases[i].z.NotZero())
- {
- bases[i].y = GetField().Multiply(bases[i].y, bases[i].z);
- bases[i].z = GetField().Square(bases[i].z);
- bases[i].x = GetField().Multiply(bases[i].x, bases[i].z);
- bases[i].y = GetField().Multiply(bases[i].y, bases[i].z);
- }
- }
-
- std::vector<BaseAndExponent<Point, Integer> > finalCascade;
- for (i=0; i<expCount; i++)
- {
- finalCascade.resize(baseIndices[i].size());
- for (unsigned int j=0; j<baseIndices[i].size(); j++)
- {
- ProjectivePoint &base = bases[baseIndices[i][j]];
- if (base.z.IsZero())
- finalCascade[j].base.identity = true;
- else
- {
- finalCascade[j].base.identity = false;
- finalCascade[j].base.x = base.x;
- if (negateBase[i][j])
- finalCascade[j].base.y = GetField().Inverse(base.y);
- else
- finalCascade[j].base.y = base.y;
- }
- finalCascade[j].exponent = Integer(Integer::POSITIVE, 0, exponentWindows[i][j]);
- }
- results[i] = GeneralCascadeMultiplication(*this, finalCascade.begin(), finalCascade.end());
- }
-}
-
-ECP::Point ECP::CascadeScalarMultiply(const Point &P, const Integer &k1, const Point &Q, const Integer &k2) const
-{
- if (!GetField().IsMontgomeryRepresentation())
- {
- ECP ecpmr(*this, true);
- const ModularArithmetic &mr = ecpmr.GetField();
- return FromMontgomery(mr, ecpmr.CascadeScalarMultiply(ToMontgomery(mr, P), k1, ToMontgomery(mr, Q), k2));
- }
- else
- return AbstractGroup<Point>::CascadeScalarMultiply(P, k1, Q, k2);
-}
-
-NAMESPACE_END
-
-#endif