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113 lines
3.1 KiB
113 lines
3.1 KiB
5 years ago
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// xtrcrypt.cpp - written and placed in the public domain by Wei Dai
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#include "pch.h"
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#include "asn.h"
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#include "integer.h"
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#include "xtrcrypt.h"
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#include "nbtheory.h"
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#include "modarith.h"
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#include "argnames.h"
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NAMESPACE_BEGIN(CryptoPP)
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XTR_DH::XTR_DH(const Integer &p, const Integer &q, const GFP2Element &g)
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: m_p(p), m_q(q), m_g(g)
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{
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}
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XTR_DH::XTR_DH(RandomNumberGenerator &rng, unsigned int pbits, unsigned int qbits)
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{
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XTR_FindPrimesAndGenerator(rng, m_p, m_q, m_g, pbits, qbits);
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}
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XTR_DH::XTR_DH(BufferedTransformation &bt)
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{
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BERSequenceDecoder seq(bt);
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m_p.BERDecode(seq);
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m_q.BERDecode(seq);
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m_g.c1.BERDecode(seq);
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m_g.c2.BERDecode(seq);
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seq.MessageEnd();
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}
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void XTR_DH::DEREncode(BufferedTransformation &bt) const
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{
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DERSequenceEncoder seq(bt);
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m_p.DEREncode(seq);
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m_q.DEREncode(seq);
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m_g.c1.DEREncode(seq);
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m_g.c2.DEREncode(seq);
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seq.MessageEnd();
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}
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bool XTR_DH::Validate(RandomNumberGenerator &rng, unsigned int level) const
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{
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bool pass = true;
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pass = pass && m_p > Integer::One() && m_p.IsOdd();
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pass = pass && m_q > Integer::One() && m_q.IsOdd();
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GFP2Element three = GFP2_ONB<ModularArithmetic>(m_p).ConvertIn(3);
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pass = pass && !(m_g.c1.IsNegative() || m_g.c2.IsNegative() || m_g.c1 >= m_p || m_g.c2 >= m_p || m_g == three);
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if (level >= 1)
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pass = pass && ((m_p.Squared()-m_p+1)%m_q).IsZero();
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if (level >= 2)
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{
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pass = pass && VerifyPrime(rng, m_p, level-2) && VerifyPrime(rng, m_q, level-2);
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pass = pass && XTR_Exponentiate(m_g, (m_p.Squared()-m_p+1)/m_q, m_p) != three;
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pass = pass && XTR_Exponentiate(m_g, m_q, m_p) == three;
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}
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return pass;
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}
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bool XTR_DH::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
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{
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return GetValueHelper(this, name, valueType, pValue).Assignable()
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CRYPTOPP_GET_FUNCTION_ENTRY(Modulus)
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CRYPTOPP_GET_FUNCTION_ENTRY(SubgroupOrder)
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CRYPTOPP_GET_FUNCTION_ENTRY(SubgroupGenerator)
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;
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}
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void XTR_DH::AssignFrom(const NameValuePairs &source)
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{
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AssignFromHelper(this, source)
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CRYPTOPP_SET_FUNCTION_ENTRY(Modulus)
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CRYPTOPP_SET_FUNCTION_ENTRY(SubgroupOrder)
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CRYPTOPP_SET_FUNCTION_ENTRY(SubgroupGenerator)
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;
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}
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void XTR_DH::GeneratePrivateKey(RandomNumberGenerator &rng, byte *privateKey) const
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{
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Integer x(rng, Integer::Zero(), m_q-1);
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x.Encode(privateKey, PrivateKeyLength());
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}
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void XTR_DH::GeneratePublicKey(RandomNumberGenerator &rng, const byte *privateKey, byte *publicKey) const
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{
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CRYPTOPP_UNUSED(rng);
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Integer x(privateKey, PrivateKeyLength());
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GFP2Element y = XTR_Exponentiate(m_g, x, m_p);
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y.Encode(publicKey, PublicKeyLength());
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}
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bool XTR_DH::Agree(byte *agreedValue, const byte *privateKey, const byte *otherPublicKey, bool validateOtherPublicKey) const
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{
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GFP2Element w(otherPublicKey, PublicKeyLength());
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if (validateOtherPublicKey)
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{
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GFP2_ONB<ModularArithmetic> gfp2(m_p);
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GFP2Element three = gfp2.ConvertIn(3);
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if (w.c1.IsNegative() || w.c2.IsNegative() || w.c1 >= m_p || w.c2 >= m_p || w == three)
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return false;
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if (XTR_Exponentiate(w, m_q, m_p) != three)
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return false;
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}
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Integer s(privateKey, PrivateKeyLength());
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GFP2Element z = XTR_Exponentiate(w, s, m_p);
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z.Encode(agreedValue, AgreedValueLength());
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return true;
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}
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NAMESPACE_END
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