Initial revision

1 files changed, 210 insertions, 0 deletions

diff --git a/esign.cpp b/esign.cpp
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+++ b/esign.cpp
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+// esign.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+#include "esign.h"
+#include "asn.h"
+#include "modarith.h"
+#include "nbtheory.h"
+#include "sha.h"
+#include "algparam.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+void ESIGN_TestInstantiations()
+{
+	ESIGN<SHA>::Verifier x1(1, 1);
+	ESIGN<SHA>::Signer x2(NullRNG(), 1);
+	ESIGN<SHA>::Verifier x3(x2);
+	ESIGN<SHA>::Verifier x4(x2.GetKey());
+	ESIGN<SHA>::Verifier x5(x3);
+	ESIGN<SHA>::Signer x6 = x2;
+
+	x6 = x2;
+	x3 = ESIGN<SHA>::Verifier(x2);
+	x4 = x2.GetKey();
+}
+
+void ESIGNFunction::BERDecode(BufferedTransformation &bt)
+{
+	BERSequenceDecoder seq(bt);
+		m_n.BERDecode(seq);
+		m_e.BERDecode(seq);
+	seq.MessageEnd();
+}
+
+void ESIGNFunction::DEREncode(BufferedTransformation &bt) const
+{
+	DERSequenceEncoder seq(bt);
+		m_n.DEREncode(seq);
+		m_e.DEREncode(seq);
+	seq.MessageEnd();
+}
+
+Integer ESIGNFunction::ApplyFunction(const Integer &x) const
+{
+	DoQuickSanityCheck();
+	return STDMIN(a_exp_b_mod_c(x, m_e, m_n) >> (2*GetK()+2), MaxImage());
+}
+
+bool ESIGNFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
+{
+	bool pass = true;
+	pass = pass && m_n > Integer::One() && m_n.IsOdd();
+	pass = pass && m_e >= 8 && m_e < m_n;
+	return pass;
+}
+
+bool ESIGNFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
+{
+	return GetValueHelper(this, name, valueType, pValue).Assignable()
+		CRYPTOPP_GET_FUNCTION_ENTRY(Modulus)
+		CRYPTOPP_GET_FUNCTION_ENTRY(PublicExponent)
+		;
+}
+
+void ESIGNFunction::AssignFrom(const NameValuePairs &source)
+{
+	AssignFromHelper(this, source)
+		CRYPTOPP_SET_FUNCTION_ENTRY(Modulus)
+		CRYPTOPP_SET_FUNCTION_ENTRY(PublicExponent)
+		;
+}
+
+// *****************************************************************************
+
+void InvertibleESIGNFunction::GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &param)
+{
+	int modulusSize = 1023*2;
+	param.GetIntValue("ModulusSize", modulusSize) || param.GetIntValue("KeySize", modulusSize);
+
+	if (modulusSize < 24)
+		throw InvalidArgument("InvertibleESIGNFunction: specified modulus size is too small");
+
+	if (modulusSize % 3 != 0)
+		throw InvalidArgument("InvertibleESIGNFunction: modulus size must be divisible by 3");
+
+	m_e = param.GetValueWithDefault("PublicExponent", Integer(32));
+
+	if (m_e < 8)
+		throw InvalidArgument("InvertibleESIGNFunction: public exponents less than 8 may not be secure");
+
+	// VC70 workaround: putting these after primeParam causes overlapped stack allocation
+	ConstByteArrayParameter seedParam;
+	SecByteBlock seed;
+
+	const Integer minP = Integer(204) << (modulusSize/3-8);
+	const Integer maxP = Integer::Power2(modulusSize/3)-1;
+	const NameValuePairs &primeParam = MakeParameters("Min", minP)("Max", maxP)("RandomNumberType", Integer::PRIME);
+
+	if (param.GetValue("Seed", seedParam))
+	{
+		seed.resize(seedParam.size() + 4);
+		memcpy(seed + 4, seedParam.begin(), seedParam.size());
+
+		UnalignedPutWord(BIG_ENDIAN_ORDER, seed, (word32)0);
+		m_p.GenerateRandom(rng, CombinedNameValuePairs(primeParam, MakeParameters("Seed", ConstByteArrayParameter(seed))));
+		UnalignedPutWord(BIG_ENDIAN_ORDER, seed, (word32)1);
+		m_q.GenerateRandom(rng, CombinedNameValuePairs(primeParam, MakeParameters("Seed", ConstByteArrayParameter(seed))));
+	}
+	else
+	{
+		m_p.GenerateRandom(rng, primeParam);
+		m_q.GenerateRandom(rng, primeParam);
+	}
+
+	m_n = m_p * m_p * m_q;
+
+	assert(m_n.BitCount() == modulusSize);
+}
+
+void InvertibleESIGNFunction::BERDecode(BufferedTransformation &bt)
+{
+	BERSequenceDecoder privateKey(bt);
+		m_n.BERDecode(privateKey);
+		m_e.BERDecode(privateKey);
+		m_p.BERDecode(privateKey);
+		m_q.BERDecode(privateKey);
+	privateKey.MessageEnd();
+}
+
+void InvertibleESIGNFunction::DEREncode(BufferedTransformation &bt) const
+{
+	DERSequenceEncoder privateKey(bt);
+		m_n.DEREncode(privateKey);
+		m_e.DEREncode(privateKey);
+		m_p.DEREncode(privateKey);
+		m_q.DEREncode(privateKey);
+	privateKey.MessageEnd();
+}
+
+Integer InvertibleESIGNFunction::CalculateRandomizedInverse(RandomNumberGenerator &rng, const Integer &x) const 
+{
+	DoQuickSanityCheck();
+
+	Integer pq = m_p * m_q;
+	Integer p2 = m_p * m_p;
+	Integer r, z, re, a, w0, w1;
+
+	do
+	{
+		r.Randomize(rng, Integer::Zero(), pq);
+		z = x << (2*GetK()+2);
+		re = a_exp_b_mod_c(r, m_e, m_n);
+		a = (z - re) % m_n;
+		Integer::Divide(w1, w0, a, pq);
+		if (w1.NotZero())
+		{
+			++w0;
+			w1 = pq - w1;
+		}
+	}
+	while ((w1 >> 2*GetK()+1).IsPositive());
+
+	ModularArithmetic modp(m_p);
+	Integer t = modp.Divide(w0 * r % m_p, m_e * re % m_p);
+	Integer s = r + t*pq;
+	assert(s < m_n);
+/*
+	using namespace std;
+	cout << "f = " << x << endl;
+	cout << "r = " << r << endl;
+	cout << "z = " << z << endl;
+	cout << "a = " << a << endl;
+	cout << "w0 = " << w0 << endl;
+	cout << "w1 = " << w1 << endl;
+	cout << "t = " << t << endl;
+	cout << "s = " << s << endl;
+*/
+	return s;
+}
+
+bool InvertibleESIGNFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
+{
+	bool pass = ESIGNFunction::Validate(rng, level);
+	pass = pass && m_p > Integer::One() && m_p.IsOdd() && m_p < m_n;
+	pass = pass && m_q > Integer::One() && m_q.IsOdd() && m_q < m_n;
+	pass = pass && m_p.BitCount() == m_q.BitCount();
+	if (level >= 1)
+		pass = pass && m_p * m_p * m_q == m_n;
+	if (level >= 2)
+		pass = pass && VerifyPrime(rng, m_p, level-2) && VerifyPrime(rng, m_q, level-2);
+	return pass;
+}
+
+bool InvertibleESIGNFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
+{
+	return GetValueHelper<ESIGNFunction>(this, name, valueType, pValue).Assignable()
+		CRYPTOPP_GET_FUNCTION_ENTRY(Prime1)
+		CRYPTOPP_GET_FUNCTION_ENTRY(Prime2)
+		;
+}
+
+void InvertibleESIGNFunction::AssignFrom(const NameValuePairs &source)
+{
+	AssignFromHelper<ESIGNFunction>(this, source)
+		CRYPTOPP_SET_FUNCTION_ENTRY(Prime1)
+		CRYPTOPP_SET_FUNCTION_ENTRY(Prime2)
+		;
+}
+
+NAMESPACE_END