00001
00002
00003 #include "pch.h"
00004 #include "rabin.h"
00005 #include "nbtheory.h"
00006 #include "asn.h"
00007 #include "sha.h"
00008 #include "modarith.h"
00009
00010 NAMESPACE_BEGIN(CryptoPP)
00011
00012 void RabinFunction::BERDecode(BufferedTransformation &bt)
00013 {
00014 BERSequenceDecoder seq(bt);
00015 m_n.BERDecode(seq);
00016 m_r.BERDecode(seq);
00017 m_s.BERDecode(seq);
00018 seq.MessageEnd();
00019 }
00020
00021 void RabinFunction::DEREncode(BufferedTransformation &bt) const
00022 {
00023 DERSequenceEncoder seq(bt);
00024 m_n.DEREncode(seq);
00025 m_r.DEREncode(seq);
00026 m_s.DEREncode(seq);
00027 seq.MessageEnd();
00028 }
00029
00030 Integer RabinFunction::ApplyFunction(const Integer &in) const
00031 {
00032 DoQuickSanityCheck();
00033
00034 Integer out = in.Squared()%m_n;
00035 if (in.IsOdd())
00036 out = out*m_r%m_n;
00037 if (Jacobi(in, m_n)==-1)
00038 out = out*m_s%m_n;
00039 return out;
00040 }
00041
00042 bool RabinFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
00043 {
00044 bool pass = true;
00045 pass = pass && m_n > Integer::One() && m_n%4 == 1;
00046 pass = pass && m_r > Integer::One() && m_r < m_n;
00047 pass = pass && m_s > Integer::One() && m_s < m_n;
00048 if (level >= 1)
00049 pass = pass && Jacobi(m_r, m_n) == -1 && Jacobi(m_s, m_n) == -1;
00050 return pass;
00051 }
00052
00053 bool RabinFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
00054 {
00055 return GetValueHelper(this, name, valueType, pValue).Assignable()
00056 CRYPTOPP_GET_FUNCTION_ENTRY(Modulus)
00057 CRYPTOPP_GET_FUNCTION_ENTRY(QuadraticResidueModPrime1)
00058 CRYPTOPP_GET_FUNCTION_ENTRY(QuadraticResidueModPrime2)
00059 ;
00060 }
00061
00062 void RabinFunction::AssignFrom(const NameValuePairs &source)
00063 {
00064 AssignFromHelper(this, source)
00065 CRYPTOPP_SET_FUNCTION_ENTRY(Modulus)
00066 CRYPTOPP_SET_FUNCTION_ENTRY(QuadraticResidueModPrime1)
00067 CRYPTOPP_SET_FUNCTION_ENTRY(QuadraticResidueModPrime2)
00068 ;
00069 }
00070
00071
00072
00073
00074
00075 void InvertibleRabinFunction::GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg)
00076 {
00077 int modulusSize = 2048;
00078 alg.GetIntValue("ModulusSize", modulusSize) || alg.GetIntValue("KeySize", modulusSize);
00079
00080 if (modulusSize < 16)
00081 throw InvalidArgument("InvertibleRabinFunction: specified modulus size is too small");
00082
00083
00084 bool rFound=false, sFound=false;
00085 Integer t=2;
00086
00087 AlgorithmParameters primeParam = MakeParametersForTwoPrimesOfEqualSize(modulusSize)
00088 ("EquivalentTo", 3)("Mod", 4);
00089 m_p.GenerateRandom(rng, primeParam);
00090 m_q.GenerateRandom(rng, primeParam);
00091
00092 while (!(rFound && sFound))
00093 {
00094 int jp = Jacobi(t, m_p);
00095 int jq = Jacobi(t, m_q);
00096
00097 if (!rFound && jp==1 && jq==-1)
00098 {
00099 m_r = t;
00100 rFound = true;
00101 }
00102
00103 if (!sFound && jp==-1 && jq==1)
00104 {
00105 m_s = t;
00106 sFound = true;
00107 }
00108
00109 ++t;
00110 }
00111
00112 m_n = m_p * m_q;
00113 m_u = m_q.InverseMod(m_p);
00114 }
00115
00116 void InvertibleRabinFunction::BERDecode(BufferedTransformation &bt)
00117 {
00118 BERSequenceDecoder seq(bt);
00119 m_n.BERDecode(seq);
00120 m_r.BERDecode(seq);
00121 m_s.BERDecode(seq);
00122 m_p.BERDecode(seq);
00123 m_q.BERDecode(seq);
00124 m_u.BERDecode(seq);
00125 seq.MessageEnd();
00126 }
00127
00128 void InvertibleRabinFunction::DEREncode(BufferedTransformation &bt) const
00129 {
00130 DERSequenceEncoder seq(bt);
00131 m_n.DEREncode(seq);
00132 m_r.DEREncode(seq);
00133 m_s.DEREncode(seq);
00134 m_p.DEREncode(seq);
00135 m_q.DEREncode(seq);
00136 m_u.DEREncode(seq);
00137 seq.MessageEnd();
00138 }
00139
00140 Integer InvertibleRabinFunction::CalculateInverse(RandomNumberGenerator &rng, const Integer &in) const
00141 {
00142 DoQuickSanityCheck();
00143
00144 ModularArithmetic modn(m_n);
00145 Integer r(rng, Integer::One(), m_n - Integer::One());
00146 r = modn.Square(r);
00147 Integer r2 = modn.Square(r);
00148 Integer c = modn.Multiply(in, r2);
00149
00150 Integer cp=c%m_p, cq=c%m_q;
00151
00152 int jp = Jacobi(cp, m_p);
00153 int jq = Jacobi(cq, m_q);
00154
00155 if (jq==-1)
00156 {
00157 cp = cp*EuclideanMultiplicativeInverse(m_r, m_p)%m_p;
00158 cq = cq*EuclideanMultiplicativeInverse(m_r, m_q)%m_q;
00159 }
00160
00161 if (jp==-1)
00162 {
00163 cp = cp*EuclideanMultiplicativeInverse(m_s, m_p)%m_p;
00164 cq = cq*EuclideanMultiplicativeInverse(m_s, m_q)%m_q;
00165 }
00166
00167 cp = ModularSquareRoot(cp, m_p);
00168 cq = ModularSquareRoot(cq, m_q);
00169
00170 if (jp==-1)
00171 cp = m_p-cp;
00172
00173 Integer out = CRT(cq, m_q, cp, m_p, m_u);
00174
00175 out = modn.Divide(out, r);
00176
00177 if ((jq==-1 && out.IsEven()) || (jq==1 && out.IsOdd()))
00178 out = m_n-out;
00179
00180 return out;
00181 }
00182
00183 bool InvertibleRabinFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
00184 {
00185 bool pass = RabinFunction::Validate(rng, level);
00186 pass = pass && m_p > Integer::One() && m_p%4 == 3 && m_p < m_n;
00187 pass = pass && m_q > Integer::One() && m_q%4 == 3 && m_q < m_n;
00188 pass = pass && m_u.IsPositive() && m_u < m_p;
00189 if (level >= 1)
00190 {
00191 pass = pass && m_p * m_q == m_n;
00192 pass = pass && m_u * m_q % m_p == 1;
00193 pass = pass && Jacobi(m_r, m_p) == 1;
00194 pass = pass && Jacobi(m_r, m_q) == -1;
00195 pass = pass && Jacobi(m_s, m_p) == -1;
00196 pass = pass && Jacobi(m_s, m_q) == 1;
00197 }
00198 if (level >= 2)
00199 pass = pass && VerifyPrime(rng, m_p, level-2) && VerifyPrime(rng, m_q, level-2);
00200 return pass;
00201 }
00202
00203 bool InvertibleRabinFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
00204 {
00205 return GetValueHelper<RabinFunction>(this, name, valueType, pValue).Assignable()
00206 CRYPTOPP_GET_FUNCTION_ENTRY(Prime1)
00207 CRYPTOPP_GET_FUNCTION_ENTRY(Prime2)
00208 CRYPTOPP_GET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
00209 ;
00210 }
00211
00212 void InvertibleRabinFunction::AssignFrom(const NameValuePairs &source)
00213 {
00214 AssignFromHelper<RabinFunction>(this, source)
00215 CRYPTOPP_SET_FUNCTION_ENTRY(Prime1)
00216 CRYPTOPP_SET_FUNCTION_ENTRY(Prime2)
00217 CRYPTOPP_SET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
00218 ;
00219 }
00220
00221 NAMESPACE_END