rsa.cpp

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// rsa.cpp - written and placed in the public domain by Wei Dai

#include "pch.h"
#include "rsa.h"
#include "asn.h"
#include "sha.h"
#include "oids.h"
#include "modarith.h"
#include "nbtheory.h"
#include "algparam.h"
#include "fips140.h"

#if defined(CRYPTOPP_DEBUG) && !defined(CRYPTOPP_DOXYGEN_PROCESSING) && !defined(CRYPTOPP_IS_DLL)
#include "pssr.h"
NAMESPACE_BEGIN(CryptoPP)
void RSA_TestInstantiations()
{
        RSASS<PKCS1v15, SHA>::Verifier x1(1, 1);
        RSASS<PKCS1v15, SHA>::Signer x2(NullRNG(), 1);
        RSASS<PKCS1v15, SHA>::Verifier x3(x2);
        RSASS<PKCS1v15, SHA>::Verifier x4(x2.GetKey());
        RSASS<PSS, SHA>::Verifier x5(x3);
#ifndef __MWERKS__
        RSASS<PSSR, SHA>::Signer x6 = x2;
        x3 = x2;
        x6 = x2;
#endif
        RSAES<PKCS1v15>::Encryptor x7(x2);
#ifndef __GNUC__
        RSAES<PKCS1v15>::Encryptor x8(x3);
#endif
        RSAES<OAEP<SHA> >::Encryptor x9(x2);

        x4 = x2.GetKey();
}
NAMESPACE_END
#endif

#ifndef CRYPTOPP_IMPORTS

NAMESPACE_BEGIN(CryptoPP)

OID RSAFunction::GetAlgorithmID() const
{
        return ASN1::rsaEncryption();
}

void RSAFunction::BERDecodePublicKey(BufferedTransformation &bt, bool, size_t)
{
        BERSequenceDecoder seq(bt);
                m_n.BERDecode(seq);
                m_e.BERDecode(seq);
        seq.MessageEnd();
}

void RSAFunction::DEREncodePublicKey(BufferedTransformation &bt) const
{
        DERSequenceEncoder seq(bt);
                m_n.DEREncode(seq);
                m_e.DEREncode(seq);
        seq.MessageEnd();
}

Integer RSAFunction::ApplyFunction(const Integer &x) const
{
        DoQuickSanityCheck();
        return a_exp_b_mod_c(x, m_e, m_n);
}

bool RSAFunction::Validate(RandomNumberGenerator& rng, unsigned int level) const
{
        CRYPTOPP_UNUSED(rng), CRYPTOPP_UNUSED(level);

        bool pass = true;
        pass = pass && m_n > Integer::One() && m_n.IsOdd();
        pass = pass && m_e > Integer::One() && m_e.IsOdd() && m_e < m_n;
        return pass;
}

bool RSAFunction::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 RSAFunction::AssignFrom(const NameValuePairs &source)
{
        AssignFromHelper(this, source)
                CRYPTOPP_SET_FUNCTION_ENTRY(Modulus)
                CRYPTOPP_SET_FUNCTION_ENTRY(PublicExponent)
                ;
}

// *****************************************************************************

class RSAPrimeSelector : public PrimeSelector
{
public:
        RSAPrimeSelector(const Integer &e) : m_e(e) {}
        bool IsAcceptable(const Integer &candidate) const {return RelativelyPrime(m_e, candidate-Integer::One());}
        Integer m_e;
};

void InvertibleRSAFunction::GenerateRandom(RandomNumberGenerator &rng, const NameValuePairs &alg)
{
        int modulusSize = 2048;
        alg.GetIntValue(Name::ModulusSize(), modulusSize) || alg.GetIntValue(Name::KeySize(), modulusSize);

        CRYPTOPP_ASSERT(modulusSize >= 16);
        if (modulusSize < 16)
                throw InvalidArgument("InvertibleRSAFunction: specified modulus size is too small");

        m_e = alg.GetValueWithDefault(Name::PublicExponent(), Integer(17));

        CRYPTOPP_ASSERT(m_e >= 3); CRYPTOPP_ASSERT(!m_e.IsEven());
        if (m_e < 3 || m_e.IsEven())
                throw InvalidArgument("InvertibleRSAFunction: invalid public exponent");

        RSAPrimeSelector selector(m_e);
        AlgorithmParameters primeParam = MakeParametersForTwoPrimesOfEqualSize(modulusSize)
                (Name::PointerToPrimeSelector(), selector.GetSelectorPointer());
        m_p.GenerateRandom(rng, primeParam);
        m_q.GenerateRandom(rng, primeParam);

        m_d = m_e.InverseMod(LCM(m_p-1, m_q-1));
        CRYPTOPP_ASSERT(m_d.IsPositive());

        m_dp = m_d % (m_p-1);
        m_dq = m_d % (m_q-1);
        m_n = m_p * m_q;
        m_u = m_q.InverseMod(m_p);

        if (FIPS_140_2_ComplianceEnabled())
        {
                RSASS<PKCS1v15, SHA>::Signer signer(*this);
                RSASS<PKCS1v15, SHA>::Verifier verifier(signer);
                SignaturePairwiseConsistencyTest_FIPS_140_Only(signer, verifier);

                RSAES<OAEP<SHA> >::Decryptor decryptor(*this);
                RSAES<OAEP<SHA> >::Encryptor encryptor(decryptor);
                EncryptionPairwiseConsistencyTest_FIPS_140_Only(encryptor, decryptor);
        }
}

void InvertibleRSAFunction::Initialize(RandomNumberGenerator &rng, unsigned int keybits, const Integer &e)
{
        GenerateRandom(rng, MakeParameters(Name::ModulusSize(), (int)keybits)(Name::PublicExponent(), e+e.IsEven()));
}

void InvertibleRSAFunction::Initialize(const Integer &n, const Integer &e, const Integer &d)
{
        if (n.IsEven() || e.IsEven() | d.IsEven())
                throw InvalidArgument("InvertibleRSAFunction: input is not a valid RSA private key");

        m_n = n;
        m_e = e;
        m_d = d;

        Integer r = --(d*e);
        unsigned int s = 0;
        while (r.IsEven())
        {
                r >>= 1;
                s++;
        }

        ModularArithmetic modn(n);
        for (Integer i = 2; ; ++i)
        {
                Integer a = modn.Exponentiate(i, r);
                if (a == 1)
                        continue;
                Integer b;
                unsigned int j = 0;
                while (a != n-1)
                {
                        b = modn.Square(a);
                        if (b == 1)
                        {
                                m_p = GCD(a-1, n);
                                m_q = n/m_p;
                                m_dp = m_d % (m_p-1);
                                m_dq = m_d % (m_q-1);
                                m_u = m_q.InverseMod(m_p);
                                return;
                        }
                        if (++j == s)
                                throw InvalidArgument("InvertibleRSAFunction: input is not a valid RSA private key");
                        a = b;
                }
        }
}

void InvertibleRSAFunction::BERDecodePrivateKey(BufferedTransformation &bt, bool, size_t)
{
        BERSequenceDecoder privateKey(bt);
                word32 version;
                BERDecodeUnsigned<word32>(privateKey, version, INTEGER, 0, 0);  // check version
                m_n.BERDecode(privateKey);
                m_e.BERDecode(privateKey);
                m_d.BERDecode(privateKey);
                m_p.BERDecode(privateKey);
                m_q.BERDecode(privateKey);
                m_dp.BERDecode(privateKey);
                m_dq.BERDecode(privateKey);
                m_u.BERDecode(privateKey);
        privateKey.MessageEnd();
}

void InvertibleRSAFunction::DEREncodePrivateKey(BufferedTransformation &bt) const
{
        DERSequenceEncoder privateKey(bt);
                DEREncodeUnsigned<word32>(privateKey, 0);       // version
                m_n.DEREncode(privateKey);
                m_e.DEREncode(privateKey);
                m_d.DEREncode(privateKey);
                m_p.DEREncode(privateKey);
                m_q.DEREncode(privateKey);
                m_dp.DEREncode(privateKey);
                m_dq.DEREncode(privateKey);
                m_u.DEREncode(privateKey);
        privateKey.MessageEnd();
}

Integer InvertibleRSAFunction::CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const
{
        DoQuickSanityCheck();
        ModularArithmetic modn(m_n);
        Integer r, rInv;
        do {    // do this in a loop for people using small numbers for testing
                r.Randomize(rng, Integer::One(), m_n - Integer::One());
                rInv = modn.MultiplicativeInverse(r);
        } while (rInv.IsZero());
        Integer re = modn.Exponentiate(r, m_e);
        re = modn.Multiply(re, x);                      // blind
        // here we follow the notation of PKCS #1 and let u=q inverse mod p
        // but in ModRoot, u=p inverse mod q, so we reverse the order of p and q
        Integer y = ModularRoot(re, m_dq, m_dp, m_q, m_p, m_u);
        y = modn.Multiply(y, rInv);                             // unblind
        if (modn.Exponentiate(y, m_e) != x)             // check
                throw Exception(Exception::OTHER_ERROR, "InvertibleRSAFunction: computational error during private key operation");
        return y;
}

bool InvertibleRSAFunction::Validate(RandomNumberGenerator &rng, unsigned int level) const
{
        bool pass = RSAFunction::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_d > Integer::One() && m_d.IsOdd() && m_d < m_n;
        pass = pass && m_dp > Integer::One() && m_dp.IsOdd() && m_dp < m_p;
        pass = pass && m_dq > Integer::One() && m_dq.IsOdd() && m_dq < m_q;
        pass = pass && m_u.IsPositive() && m_u < m_p;
        if (level >= 1)
        {
                pass = pass && m_p * m_q == m_n;
                pass = pass && m_e*m_d % LCM(m_p-1, m_q-1) == 1;
                pass = pass && m_dp == m_d%(m_p-1) && m_dq == m_d%(m_q-1);
                pass = pass && m_u * m_q % m_p == 1;
        }
        if (level >= 2)
                pass = pass && VerifyPrime(rng, m_p, level-2) && VerifyPrime(rng, m_q, level-2);
        return pass;
}

bool InvertibleRSAFunction::GetVoidValue(const char *name, const std::type_info &valueType, void *pValue) const
{
        return GetValueHelper<RSAFunction>(this, name, valueType, pValue).Assignable()
                CRYPTOPP_GET_FUNCTION_ENTRY(Prime1)
                CRYPTOPP_GET_FUNCTION_ENTRY(Prime2)
                CRYPTOPP_GET_FUNCTION_ENTRY(PrivateExponent)
                CRYPTOPP_GET_FUNCTION_ENTRY(ModPrime1PrivateExponent)
                CRYPTOPP_GET_FUNCTION_ENTRY(ModPrime2PrivateExponent)
                CRYPTOPP_GET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
                ;
}

void InvertibleRSAFunction::AssignFrom(const NameValuePairs &source)
{
        AssignFromHelper<RSAFunction>(this, source)
                CRYPTOPP_SET_FUNCTION_ENTRY(Prime1)
                CRYPTOPP_SET_FUNCTION_ENTRY(Prime2)
                CRYPTOPP_SET_FUNCTION_ENTRY(PrivateExponent)
                CRYPTOPP_SET_FUNCTION_ENTRY(ModPrime1PrivateExponent)
                CRYPTOPP_SET_FUNCTION_ENTRY(ModPrime2PrivateExponent)
                CRYPTOPP_SET_FUNCTION_ENTRY(MultiplicativeInverseOfPrime2ModPrime1)
                ;
}

// *****************************************************************************

Integer RSAFunction_ISO::ApplyFunction(const Integer &x) const
{
        Integer t = RSAFunction::ApplyFunction(x);
        return t % 16 == 12 ? t : m_n - t;
}

Integer InvertibleRSAFunction_ISO::CalculateInverse(RandomNumberGenerator &rng, const Integer &x) const
{
        Integer t = InvertibleRSAFunction::CalculateInverse(rng, x);
        return STDMIN(t, m_n-t);
}

NAMESPACE_END

#endif