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# rsa.cpp

    00001 // rsa.cpp - written and placed in the public domain by Wei Dai
    00002
    00003 #include "pch.h"
    00004 #include "rsa.h"
    00005 #include "asn.h"
    00006 #include "oids.h"
    00007 #include "modarith.h"
    00008 #include "nbtheory.h"
    00009 #include "sha.h"
    00010 #include "algparam.h"
    00011 #include "fips140.h"
    00012 #include "randpool.h"
    00013
    00014 NAMESPACE_BEGIN(CryptoPP)
    00015
    00016 byte OAEP_P_DEFAULT[1];
    00017
    00018 #ifndef NDEBUG
    00019 void RSA_TestInstantiations()
    00020 {
    00021         RSASSA<PKCS1v15, SHA>::Verifier x1(1, 1);
    00022         RSASSA<PKCS1v15, SHA>::Signer x2(NullRNG(), 1);
    00023         RSASSA<PKCS1v15, SHA>::Verifier x3(x2);
    00024         RSASSA<PKCS1v15, SHA>::Verifier x4(x2.GetKey());
    00025         RSASSA<PKCS1v15, SHA>::Verifier x5(x3);
    00026         RSASSA<PKCS1v15, SHA>::Signer x6 = x2;
    00027         RSAES<PKCS1v15>::Encryptor x7(x2);
    00028         RSAES<PKCS1v15>::Encryptor x8(x3);
    00029         RSAES<OAEP<SHA> >::Encryptor x9(x2);
    00030
    00031         x6 = x2;
    00032 #ifndef __MWERKS__
    00033         x3 = x2;
    00034 #endif
    00035         x4 = x2.GetKey();
    00036 }
    00037 #endif
    00038
    00039 #ifndef CRYPTOPP_IMPORTS
    00040
    00041 OID RSAFunction::GetAlgorithmID() const
    00042 {
    00043         return ASN1::rsaEncryption();
    00044 }
    00045
    00046 void RSAFunction::BERDecodeKey(BufferedTransformation &bt)
    00047 {
    00048         BERSequenceDecoder seq(bt);
    00049                 m_n.BERDecode(seq);
    00050                 m_e.BERDecode(seq);
    00051         seq.MessageEnd();
    00052 }
    00053
    00054 void RSAFunction::DEREncodeKey(BufferedTransformation &bt) const
    00055 {
    00056         DERSequenceEncoder seq(bt);
    00057                 m_n.DEREncode(seq);
    00058                 m_e.DEREncode(seq);
    00059         seq.MessageEnd();
    00060 }
    00061
    00062 Integer RSAFunction::ApplyFunction(const Integer &x) const
    00063 {
    00064         DoQuickSanityCheck();
    00065         return a_exp_b_mod_c(x, m_e, m_n);
    00066 }
    00067
    00068 bool RSAFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
    00069 {
    00070         bool pass = true;
    00071         pass = pass && m_n > Integer::One() && m_n.IsOdd();
    00072         pass = pass && m_e > Integer::One() && m_e.IsOdd() && m_e < m_n;
    00073         return pass;
    00074 }
    00075
    00076 bool RSAFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
    00077 {
    00078         return GetValueHelper(this, name, valueType, pValue).Assignable()
    00079                 CRYPTOPP_GET_FUNCTION_ENTRY(Modulus)
    00080                 CRYPTOPP_GET_FUNCTION_ENTRY(PublicExponent)
    00081                 ;
    00082 }
    00083
    00084 void RSAFunction::AssignFrom(const NameValuePairs &source)
    00085 {
    00086         AssignFromHelper(this, source)
    00087                 CRYPTOPP_SET_FUNCTION_ENTRY(Modulus)
    00088                 CRYPTOPP_SET_FUNCTION_ENTRY(PublicExponent)
    00089                 ;
    00090 }
    00091
    00092 // *****************************************************************************
    00093
    00094 class RSAPrimeSelector : public PrimeSelector
    00095 {
    00096 public:
    00097         RSAPrimeSelector(const Integer &e) : m_e(e) {}
    00098         bool IsAcceptable(const Integer &candidate) const {return RelativelyPrime(m_e, candidate-Integer::One());}
    00099         Integer m_e;
    00100 };
    00101
    00102 void InvertibleRSAFunction::GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg)
    00103 {
    00104         int modulusSize = 2048;
    00105         alg.GetIntValue("ModulusSize", modulusSize) || alg.GetIntValue("KeySize", modulusSize);
    00106
    00107         if (modulusSize < 16)
    00108                 throw InvalidArgument("InvertibleRSAFunction: specified modulus size is too small");
    00109
    00110         m_e = alg.GetValueWithDefault("PublicExponent", Integer(17));
    00111
    00112         if (m_e < 3 || m_e.IsEven())
    00113                 throw InvalidArgument("InvertibleRSAFunction: invalid public exponent");
    00114
    00115         RSAPrimeSelector selector(m_e);
    00116         const NameValuePairs &primeParam = MakeParametersForTwoPrimesOfEqualSize(modulusSize)
    00117                 ("PointerToPrimeSelector", selector.GetSelectorPointer());
    00118         m_p.GenerateRandom(rng, primeParam);
    00119         m_q.GenerateRandom(rng, primeParam);
    00120
    00121         m_d = EuclideanMultiplicativeInverse(m_e, LCM(m_p-1, m_q-1));
    00122         assert(m_d.IsPositive());
    00123
    00124         m_dp = m_d % (m_p-1);
    00125         m_dq = m_d % (m_q-1);
    00126         m_n = m_p * m_q;
    00127         m_u = m_q.InverseMod(m_p);
    00128
    00129         if (FIPS_140_2_ComplianceEnabled())
    00130         {
    00131                 RSASSA<PKCS1v15, SHA>::Signer signer(*this);
    00132                 RSASSA<PKCS1v15, SHA>::Verifier verifier(signer);
    00133                 SignaturePairwiseConsistencyTest(signer, verifier);
    00134
    00135                 RSAES<OAEP<SHA> >::Decryptor decryptor(*this);
    00136                 RSAES<OAEP<SHA> >::Encryptor encryptor(decryptor);
    00137                 EncryptionPairwiseConsistencyTest(encryptor, decryptor);
    00138         }
    00139 }
    00140
    00141 void InvertibleRSAFunction::Initialize(RandomNumberGenerator &rng, unsigned int keybits, const Integer &e)
    00142 {
    00143         GenerateRandom(rng, MakeParameters("ModulusSize", (int)keybits)("PublicExponent", e+e.IsEven()));
    00144 }
    00145
    00146 void InvertibleRSAFunction::BERDecodeKey(BufferedTransformation &bt)
    00147 {
    00148         BERSequenceDecoder privateKey(bt);
    00149                 word32 version;
    00150                 BERDecodeUnsigned<word32>(privateKey, version, INTEGER, 0, 0);  // check version
    00151                 m_n.BERDecode(privateKey);
    00152                 m_e.BERDecode(privateKey);
    00153                 m_d.BERDecode(privateKey);
    00154                 m_p.BERDecode(privateKey);
    00155                 m_q.BERDecode(privateKey);
    00156                 m_dp.BERDecode(privateKey);
    00157                 m_dq.BERDecode(privateKey);
    00158                 m_u.BERDecode(privateKey);
    00159         privateKey.MessageEnd();
    00160 }
    00161
    00162 void InvertibleRSAFunction::DEREncodeKey(BufferedTransformation &bt) const
    00163 {
    00164         DERSequenceEncoder privateKey(bt);
    00165                 DEREncodeUnsigned<word32>(privateKey, 0);       // version
    00166                 m_n.DEREncode(privateKey);
    00167                 m_e.DEREncode(privateKey);
    00168                 m_d.DEREncode(privateKey);
    00169                 m_p.DEREncode(privateKey);
    00170                 m_q.DEREncode(privateKey);
    00171                 m_dp.DEREncode(privateKey);
    00172                 m_dq.DEREncode(privateKey);
    00173                 m_u.DEREncode(privateKey);
    00174         privateKey.MessageEnd();
    00175 }
    00176
    00177 Integer InvertibleRSAFunction::CalculateInverse(const Integer &x) const
    00178 {
    00179         DoQuickSanityCheck();
    00180         ModularArithmetic modn(m_n);
    00181         Integer r, rInv;
    00182         // seed rng with private key and ciphertext
    00183         RandomPool rng;
    00184         m_d.DEREncode(rng);
    00185         x.DEREncode(rng);
    00186         do {    // do this loop for people using small numbers for testing
    00187                 r.Randomize(rng, Integer::One(), m_n - Integer::One());
    00188                 rInv = modn.MultiplicativeInverse(r);
    00189         } while (rInv.IsZero());
    00190         Integer re = modn.Exponentiate(r, m_e);
    00191         re = modn.Multiply(re, x);                      // blind
    00192         // here we follow the notation of PKCS #1 and let u=q inverse mod p
    00193         // but in ModRoot, u=p inverse mod q, so we reverse the order of p and q
    00194         Integer y = ModularRoot(re, m_dq, m_dp, m_q, m_p, m_u);
    00195         y = modn.Multiply(y, rInv);                             // unblind
    00196         if (modn.Exponentiate(y, m_e) != x)             // check
    00197                 throw Exception(Exception::OTHER_ERROR, "InvertibleRSAFunction: computational error during private key operation");
    00198         return y;
    00199 }
    00200
    00201 bool InvertibleRSAFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
    00202 {
    00203         bool pass = RSAFunction::Validate(rng, level);
    00204         pass = pass && m_p > Integer::One() && m_p.IsOdd() && m_p < m_n;
    00205         pass = pass && m_q > Integer::One() && m_q.IsOdd() && m_q < m_n;
    00206         pass = pass && m_d > Integer::One() && m_d.IsOdd() && m_d < m_n;
    00207         pass = pass && m_dp > Integer::One() && m_dp.IsOdd() && m_dp < m_p;
    00208         pass = pass && m_dq > Integer::One() && m_dq.IsOdd() && m_dq < m_q;
    00209         pass = pass && m_u.IsPositive() && m_u < m_p;
    00210         if (level >= 1)
    00211         {
    00212                 pass = pass && m_p * m_q == m_n;
    00213                 pass = pass && m_e*m_d % LCM(m_p-1, m_q-1) == 1;
    00214                 pass = pass && m_dp == m_d%(m_p-1) && m_dq == m_d%(m_q-1);
    00215                 pass = pass && m_u * m_q % m_p == 1;
    00216         }
    00217         if (level >= 2)
    00218                 pass = pass && VerifyPrime(rng, m_p, level-2) && VerifyPrime(rng, m_q, level-2);
    00219         return pass;
    00220 }
    00221
    00222 bool InvertibleRSAFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
    00223 {
    00224         return GetValueHelper<RSAFunction>(this, name, valueType, pValue).Assignable()
    00225                 CRYPTOPP_GET_FUNCTION_ENTRY(Prime1)
    00226                 CRYPTOPP_GET_FUNCTION_ENTRY(Prime2)
    00227                 CRYPTOPP_GET_FUNCTION_ENTRY(PrivateExponent)
    00228                 CRYPTOPP_GET_FUNCTION_ENTRY(ModPrime1PrivateExponent)
    00229                 CRYPTOPP_GET_FUNCTION_ENTRY(ModPrime2PrivateExponent)
    00230                 CRYPTOPP_GET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
    00231                 ;
    00232 }
    00233
    00234 void InvertibleRSAFunction::AssignFrom(const NameValuePairs &source)
    00235 {
    00236         AssignFromHelper<RSAFunction>(this, source)
    00237                 CRYPTOPP_SET_FUNCTION_ENTRY(Prime1)
    00238                 CRYPTOPP_SET_FUNCTION_ENTRY(Prime2)
    00239                 CRYPTOPP_SET_FUNCTION_ENTRY(PrivateExponent)
    00240                 CRYPTOPP_SET_FUNCTION_ENTRY(ModPrime1PrivateExponent)
    00241                 CRYPTOPP_SET_FUNCTION_ENTRY(ModPrime2PrivateExponent)
    00242                 CRYPTOPP_SET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
    00243                 ;
    00244 }
    00245
    00246 #endif
    00247
    00248 /*
    00249 bool RSAFunctionInverse_NonCRT::Validate(RandomNumberGenerator &rng, unsigned int level) const
    00250 {
    00251         bool pass = true;
    00252         pass = pass && m_n > Integer::One() && m_n.IsOdd();
    00253         pass = pass && m_d > Integer::One() && m_d.IsOdd() && m_d < m_n;
    00254         return pass;
    00255 }
    00256 */
    00257
    00258 NAMESPACE_END