rsa.cpp

// rsa.cpp - originally 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"
#include "pkcspad.h"

#if defined(CRYPTOPP_DEBUG) && !defined(CRYPTOPP_DOXYGEN_PROCESSING) && !defined(CRYPTOPP_IS_DLL)
#include "sha3.h"
#include "pssr.h"
NAMESPACE_BEGIN(CryptoPP)
void RSA_TestInstantiations()
{
    RSASS<PKCS1v15, SHA1>::Verifier x1(1, 1);
    RSASS<PKCS1v15, SHA1>::Signer x2(NullRNG(), 1);
    RSASS<PKCS1v15, SHA1>::Verifier x3(x2);
    RSASS<PKCS1v15, SHA1>::Verifier x4(x2.GetKey());
    RSASS<PSS, SHA1>::Verifier x5(x3);
#ifndef __MWERKS__
    RSASS<PSSR, SHA1>::Signer x6 = x2;
    x3 = x2;
    x6 = x2;
#endif
    RSAES<PKCS1v15>::Encryptor x7(x2);
#ifndef __GNUC__
    RSAES<PKCS1v15>::Encryptor x8(x3);
#endif
    RSAES<OAEP<SHA1> >::Encryptor x9(x2);
    x4 = x2.GetKey();

    RSASS<PKCS1v15, SHA3_256>::Verifier x10(1, 1);
    RSASS<PKCS1v15, SHA3_256>::Signer x11(NullRNG(), 1);
    RSASS<PKCS1v15, SHA3_256>::Verifier x12(x11);
    RSASS<PKCS1v15, SHA3_256>::Verifier x13(x11.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();
    CRYPTOPP_ASSERT(pass);
    pass = pass && m_e > Integer::One() && m_e.IsOdd() && m_e < m_n;
    CRYPTOPP_ASSERT(pass);
    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");

    // Do this in a loop for small moduli. For small moduli, u' == 0 when p == q.
    // https://github.com/weidai11/cryptopp/issues/1136
    do
    {
        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);
    } while (m_u.IsZero());

    if (FIPS_140_2_ComplianceEnabled())
    {
        RSASS<PKCS1v15, SHA1>::Signer signer(*this);
        RSASS<PKCS1v15, SHA1>::Verifier verifier(signer);
        SignaturePairwiseConsistencyTest_FIPS_140_Only(signer, verifier);

        RSAES<OAEP<SHA1> >::Decryptor decryptor(*this);
        RSAES<OAEP<SHA1> >::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);
    CRYPTOPP_ASSERT(pass);
    pass = pass && m_p > Integer::One() && m_p.IsOdd() && m_p < m_n;
    CRYPTOPP_ASSERT(pass);
    pass = pass && m_q > Integer::One() && m_q.IsOdd() && m_q < m_n;
    CRYPTOPP_ASSERT(pass);
    pass = pass && m_d > Integer::One() && m_d.IsOdd() && m_d < m_n;
    CRYPTOPP_ASSERT(pass);
    pass = pass && m_dp > Integer::One() && m_dp.IsOdd() && m_dp < m_p;
    CRYPTOPP_ASSERT(pass);
    pass = pass && m_dq > Integer::One() && m_dq.IsOdd() && m_dq < m_q;
    CRYPTOPP_ASSERT(pass);
    pass = pass && m_u.IsPositive() && m_u < m_p;
    CRYPTOPP_ASSERT(pass);
    if (level >= 1)
    {
        pass = pass && m_p * m_q == m_n;
        CRYPTOPP_ASSERT(pass);
        pass = pass && m_e*m_d % LCM(m_p-1, m_q-1) == 1;
        CRYPTOPP_ASSERT(pass);
        pass = pass && m_dp == m_d%(m_p-1) && m_dq == m_d%(m_q-1);
        CRYPTOPP_ASSERT(pass);
        pass = pass && m_u * m_q % m_p == 1;
        CRYPTOPP_ASSERT(pass);
    }
    if (level >= 2)
    {
        pass = pass && VerifyPrime(rng, m_p, level-2) && VerifyPrime(rng, m_q, level-2);
        CRYPTOPP_ASSERT(pass);
    }
    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