default.cpp

// default.cpp - originally written and placed in the public domain by Wei Dai
 
#include "pch.h"
#include "config.h"
 
#if CRYPTOPP_MSC_VERSION
# pragma warning(disable: 4127 4189)
#endif
 
#include "cryptlib.h"
#include "filters.h"
#include "smartptr.h"
#include "default.h"
#include "queue.h"
 
#include <time.h>
#include <memory>
 
NAMESPACE_BEGIN(CryptoPP)
 
// The purpose of this function Mash() is to take an arbitrary length input
// string and *deterministically* produce an arbitrary length output string such
// that (1) it looks random, (2) no information about the input is
// deducible from it, and (3) it contains as much entropy as it can hold, or
// the amount of entropy in the input string, whichever is smaller.
 
template <class H>
static void Mash(const byte *in, size_t inLen, byte *out, size_t outLen, int iterations)
{
    if (BytePrecision(outLen) > 2)
        throw InvalidArgument("Mash: output length too large");
 
    size_t bufSize = RoundUpToMultipleOf(outLen, (size_t)H::DIGESTSIZE);
    byte b[2];
    SecByteBlock buf(bufSize);
    SecByteBlock outBuf(bufSize);
    H hash;
 
    unsigned int i;
    for(i=0; i<outLen; i+=H::DIGESTSIZE)
    {
        b[0] = (byte) (i >> 8);
        b[1] = (byte) i;
        hash.Update(b, 2);
        hash.Update(in, inLen);
        hash.Final(outBuf+i);
    }
 
    while (iterations-- > 1)
    {
        memcpy(buf, outBuf, bufSize);
        for (i=0; i<bufSize; i+=H::DIGESTSIZE)
        {
            b[0] = (byte) (i >> 8);
            b[1] = (byte) i;
            hash.Update(b, 2);
            hash.Update(buf, bufSize);
            hash.Final(outBuf+i);
        }
    }
 
    memcpy(out, outBuf, outLen);
}
 
template <class BC, class H, class Info>
static void GenerateKeyIV(const byte *passphrase, size_t passphraseLength, const byte *salt, size_t saltLength, unsigned int iterations, byte *key, byte *IV)
{
    // UBsan. User supplied params, may be NULL
    SecByteBlock temp(passphraseLength+saltLength);
    if (passphrase != NULLPTR)
        memcpy(temp, passphrase, passphraseLength);
    if (salt != NULLPTR)
        memcpy(temp+passphraseLength, salt, saltLength);
 
    // OK. Derived params, cannot be NULL
    SecByteBlock keyIV(EnumToInt(Info::KEYLENGTH)+EnumToInt(+Info::BLOCKSIZE));
    Mash<H>(temp, passphraseLength + saltLength, keyIV, EnumToInt(Info::KEYLENGTH)+EnumToInt(+Info::BLOCKSIZE), iterations);
    memcpy(key, keyIV, Info::KEYLENGTH);
    memcpy(IV, keyIV+Info::KEYLENGTH, Info::BLOCKSIZE);
}
 
// ********************************************************
 
template <class BC, class H, class Info>
DataEncryptor<BC,H,Info>::DataEncryptor(const char *passphrase, BufferedTransformation *attachment)
    : ProxyFilter(NULLPTR, 0, 0, attachment), m_passphrase((const byte *)passphrase, strlen(passphrase))
{
    CRYPTOPP_COMPILE_ASSERT((int)SALTLENGTH <= DIGESTSIZE);
    CRYPTOPP_COMPILE_ASSERT((int)BLOCKSIZE <= (int)DIGESTSIZE);
}
 
template <class BC, class H, class Info>
DataEncryptor<BC,H,Info>::DataEncryptor(const byte *passphrase, size_t passphraseLength, BufferedTransformation *attachment)
    : ProxyFilter(NULLPTR, 0, 0, attachment), m_passphrase(passphrase, passphraseLength)
{
    CRYPTOPP_COMPILE_ASSERT((int)SALTLENGTH <= (int)DIGESTSIZE);
    CRYPTOPP_COMPILE_ASSERT((int)BLOCKSIZE <= (int)DIGESTSIZE);
}
 
template <class BC, class H, class Info>
void DataEncryptor<BC,H,Info>::FirstPut(const byte *)
{
    SecByteBlock salt(DIGESTSIZE), keyCheck(DIGESTSIZE);
    H hash;
 
    // use hash(passphrase | time | clock) as salt
    hash.Update(m_passphrase, m_passphrase.size());
    time_t t=time(NULLPTR);
    hash.Update((byte *)&t, sizeof(t));
    clock_t c=clock();
    hash.Update((byte *)&c, sizeof(c));
    hash.Final(salt);
 
    // use hash(passphrase | salt) as key check
    hash.Update(m_passphrase, m_passphrase.size());
    hash.Update(salt, SALTLENGTH);
    hash.Final(keyCheck);
 
    AttachedTransformation()->Put(salt, SALTLENGTH);
 
    // mash passphrase and salt together into key and IV
    SecByteBlock key(KEYLENGTH);
    SecByteBlock IV(BLOCKSIZE);
    GenerateKeyIV<BC,H,Info>(m_passphrase, m_passphrase.size(), salt, SALTLENGTH, ITERATIONS, key, IV);
 
    m_cipher.SetKeyWithIV(key, key.size(), IV);
    SetFilter(new StreamTransformationFilter(m_cipher));
 
    m_filter->Put(keyCheck, BLOCKSIZE);
}
 
template <class BC, class H, class Info>
void DataEncryptor<BC,H,Info>::LastPut(const byte *inString, size_t length)
{
    CRYPTOPP_UNUSED(inString); CRYPTOPP_UNUSED(length);
    m_filter->MessageEnd();
}
 
// ********************************************************
 
template <class BC, class H, class Info>
DataDecryptor<BC,H,Info>::DataDecryptor(const char *p, BufferedTransformation *attachment, bool throwException)
    : ProxyFilter(NULLPTR, EnumToInt(SALTLENGTH)+EnumToInt(BLOCKSIZE), 0, attachment)
    , m_state(WAITING_FOR_KEYCHECK)
    , m_passphrase((const byte *)p, strlen(p))
    , m_throwException(throwException)
{
    CRYPTOPP_COMPILE_ASSERT((int)SALTLENGTH <= (int)DIGESTSIZE);
    CRYPTOPP_COMPILE_ASSERT((int)BLOCKSIZE <= (int)DIGESTSIZE);
}
 
template <class BC, class H, class Info>
DataDecryptor<BC,H,Info>::DataDecryptor(const byte *passphrase, size_t passphraseLength, BufferedTransformation *attachment, bool throwException)
    : ProxyFilter(NULLPTR, EnumToInt(SALTLENGTH)+EnumToInt(BLOCKSIZE), 0, attachment)
    , m_state(WAITING_FOR_KEYCHECK)
    , m_passphrase(passphrase, passphraseLength)
    , m_throwException(throwException)
{
    CRYPTOPP_COMPILE_ASSERT((int)SALTLENGTH <= (int)DIGESTSIZE);
    CRYPTOPP_COMPILE_ASSERT((int)BLOCKSIZE <= (int)DIGESTSIZE);
}
 
template <class BC, class H, class Info>
void DataDecryptor<BC,H,Info>::FirstPut(const byte *inString)
{
    CheckKey(inString, inString+SALTLENGTH);
}
 
template <class BC, class H, class Info>
void DataDecryptor<BC,H,Info>::LastPut(const byte *inString, size_t length)
{
    CRYPTOPP_UNUSED(inString); CRYPTOPP_UNUSED(length);
    if (m_filter.get() == NULLPTR)
    {
        m_state = KEY_BAD;
        if (m_throwException)
            throw KeyBadErr();
    }
    else
    {
        m_filter->MessageEnd();
        m_state = WAITING_FOR_KEYCHECK;
    }
}
 
template <class BC, class H, class Info>
void DataDecryptor<BC,H,Info>::CheckKey(const byte *salt, const byte *keyCheck)
{
    SecByteBlock check(STDMAX((unsigned int)2*BLOCKSIZE, (unsigned int)DIGESTSIZE));
 
    H hash;
    hash.Update(m_passphrase, m_passphrase.size());
    hash.Update(salt, SALTLENGTH);
    hash.Final(check);
 
    SecByteBlock key(KEYLENGTH);
    SecByteBlock IV(BLOCKSIZE);
    GenerateKeyIV<BC,H,Info>(m_passphrase, m_passphrase.size(), salt, SALTLENGTH, ITERATIONS, key, IV);
 
    m_cipher.SetKeyWithIV(key, key.size(), IV);
    member_ptr<StreamTransformationFilter> decryptor(new StreamTransformationFilter(m_cipher));
 
    decryptor->Put(keyCheck, BLOCKSIZE);
    decryptor->ForceNextPut();
    decryptor->Get(check+EnumToInt(BLOCKSIZE), BLOCKSIZE);
 
    SetFilter(decryptor.release());
 
    if (!VerifyBufsEqual(check, check+EnumToInt(BLOCKSIZE), BLOCKSIZE))
    {
        m_state = KEY_BAD;
        if (m_throwException)
            throw KeyBadErr();
    }
    else
        m_state = KEY_GOOD;
}
 
// ********************************************************
 
template <class H, class MAC>
static MAC* NewDataEncryptorMAC(const byte *passphrase, size_t passphraseLength)
{
    size_t macKeyLength = MAC::StaticGetValidKeyLength(16);
    SecByteBlock macKey(macKeyLength);
    // since the MAC is encrypted there is no reason to mash the passphrase for many iterations
    Mash<H>(passphrase, passphraseLength, macKey, macKeyLength, 1);
    return new MAC(macKey, macKeyLength);
}
 
template <class BC, class H, class MAC, class Info>
DataEncryptorWithMAC<BC,H,MAC,Info>::DataEncryptorWithMAC(const char *passphrase, BufferedTransformation *attachment)
    : ProxyFilter(NULLPTR, 0, 0, attachment)
    , m_mac(NewDataEncryptorMAC<H,MAC>((const byte *)passphrase, strlen(passphrase)))
{
    SetFilter(new HashFilter(*m_mac, new DataEncryptor<BC,H,Info>(passphrase), true));
}
 
template <class BC, class H, class MAC, class Info>
DataEncryptorWithMAC<BC,H,MAC,Info>::DataEncryptorWithMAC(const byte *passphrase, size_t passphraseLength, BufferedTransformation *attachment)
    : ProxyFilter(NULLPTR, 0, 0, attachment)
    , m_mac(NewDataEncryptorMAC<H,MAC>(passphrase, passphraseLength))
{
    SetFilter(new HashFilter(*m_mac, new DataEncryptor<BC,H,Info>(passphrase, passphraseLength), true));
}
 
template <class BC, class H, class MAC, class Info>
void DataEncryptorWithMAC<BC,H,MAC,Info>::LastPut(const byte *inString, size_t length)
{
    CRYPTOPP_UNUSED(inString); CRYPTOPP_UNUSED(length);
    m_filter->MessageEnd();
}
 
// ********************************************************
 
template <class BC, class H, class MAC, class Info>
DataDecryptorWithMAC<BC,H,MAC,Info>::DataDecryptorWithMAC(const char *passphrase, BufferedTransformation *attachment, bool throwException)
    : ProxyFilter(NULLPTR, 0, 0, attachment)
    , m_mac(NewDataEncryptorMAC<H,MAC>((const byte *)passphrase, strlen(passphrase)))
    , m_throwException(throwException)
{
    SetFilter(new DataDecryptor<BC,H,Info>(passphrase, m_hashVerifier=new HashVerificationFilter(*m_mac, NULLPTR, HashVerificationFilter::PUT_MESSAGE), throwException));
}
 
template <class BC, class H, class MAC, class Info>
DataDecryptorWithMAC<BC,H,MAC,Info>::DataDecryptorWithMAC(const byte *passphrase, size_t passphraseLength, BufferedTransformation *attachment, bool throwException)
    : ProxyFilter(NULLPTR, 0, 0, attachment)
    , m_mac(NewDataEncryptorMAC<H,MAC>(passphrase, passphraseLength))
    , m_throwException(throwException)
{
    SetFilter(new DataDecryptor<BC,H,Info>(passphrase, passphraseLength, m_hashVerifier=new HashVerificationFilter(*m_mac, NULLPTR, HashVerificationFilter::PUT_MESSAGE), throwException));
}
 
template <class BC, class H, class MAC, class Info>
typename DataDecryptor<BC,H,Info>::State DataDecryptorWithMAC<BC,H,MAC,Info>::CurrentState() const
{
    return static_cast<const DataDecryptor<BC,H,Info> *>(m_filter.get())->CurrentState();
}
 
template <class BC, class H, class MAC, class Info>
bool DataDecryptorWithMAC<BC,H,MAC,Info>::CheckLastMAC() const
{
    return m_hashVerifier->GetLastResult();
}
 
template <class BC, class H, class MAC, class Info>
void DataDecryptorWithMAC<BC,H,MAC,Info>::LastPut(const byte *inString, size_t length)
{
    CRYPTOPP_UNUSED(inString); CRYPTOPP_UNUSED(length);
    m_filter->MessageEnd();
    if (m_throwException && !CheckLastMAC())
        throw MACBadErr();
}
 
template struct DataParametersInfo<LegacyBlockCipher::BLOCKSIZE, LegacyBlockCipher::DEFAULT_KEYLENGTH, LegacyHashModule::DIGESTSIZE, 8, 200>;
template struct DataParametersInfo<DefaultBlockCipher::BLOCKSIZE, DefaultBlockCipher::DEFAULT_KEYLENGTH, DefaultHashModule::DIGESTSIZE, 8, 2500>;
 
template class DataEncryptor<LegacyBlockCipher,LegacyHashModule,LegacyParametersInfo>;
template class DataDecryptor<LegacyBlockCipher,LegacyHashModule,LegacyParametersInfo>;
template class DataEncryptor<DefaultBlockCipher,DefaultHashModule,DefaultParametersInfo>;
template class DataDecryptor<DefaultBlockCipher,DefaultHashModule,DefaultParametersInfo>;
template class DataEncryptorWithMAC<LegacyBlockCipher,LegacyHashModule,LegacyMAC,LegacyParametersInfo>;
template class DataDecryptorWithMAC<LegacyBlockCipher,LegacyHashModule,LegacyMAC,LegacyParametersInfo>;
template class DataEncryptorWithMAC<DefaultBlockCipher,DefaultHashModule,DefaultMAC,DefaultParametersInfo>;
template class DataDecryptorWithMAC<DefaultBlockCipher,DefaultHashModule,DefaultMAC,DefaultParametersInfo>;
 
NAMESPACE_END