crypter.cpp

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// Copyright (c) 2009-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#include "crypter.h"
 
#include "crypto/aes.h"
#include "crypto/sha512.h"
#include "script/script.h"
#include "script/standard.h"
#include "util.h"
 
#include <string>
#include <vector>
 
int CCrypter::BytesToKeySHA512AES(const std::vector<unsigned char>& chSalt, const SecureString& strKeyData, int count, unsigned char *key,unsigned char *iv) const
{
    // This mimics the behavior of openssl's EVP_BytesToKey with an aes256cbc
    // cipher and sha512 message digest. Because sha512's output size (64b) is
    // greater than the aes256 block size (16b) + aes256 key size (32b),
    // there's no need to process more than once (D_0).
 
    if(!count || !key || !iv)
        return 0;
 
    unsigned char buf[CSHA512::OUTPUT_SIZE];
    CSHA512 di;
 
    di.Write((const unsigned char*)strKeyData.c_str(), strKeyData.size());
    if(chSalt.size())
        di.Write(&chSalt[0], chSalt.size());
    di.Finalize(buf);
 
    for(int i = 0; i != count - 1; i++)
        di.Reset().Write(buf, sizeof(buf)).Finalize(buf);
 
    memcpy(key, buf, WALLET_CRYPTO_KEY_SIZE);
    memcpy(iv, buf + WALLET_CRYPTO_KEY_SIZE, WALLET_CRYPTO_IV_SIZE);
    memory_cleanse(buf, sizeof(buf));
    return WALLET_CRYPTO_KEY_SIZE;
}
 
bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
{
    if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
        return false;
 
    int i = 0;
    if (nDerivationMethod == 0)
        i = BytesToKeySHA512AES(chSalt, strKeyData, nRounds, chKey, chIV);
 
    if (i != (int)WALLET_CRYPTO_KEY_SIZE) {
        memory_cleanse(chKey, sizeof(chKey));
        memory_cleanse(chIV, sizeof(chIV));
        return false;
    }
 
    fKeySet = true;
    return true;
}
 
bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
{
    if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_IV_SIZE)
        return false;
 
    memcpy(&chKey[0], &chNewKey[0], sizeof chKey);
    memcpy(&chIV[0], &chNewIV[0], sizeof chIV);
 
    fKeySet = true;
    return true;
}
 
bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char>& vchCiphertext) const
{
    if (!fKeySet)
        return false;
 
    // max ciphertext len for a n bytes of plaintext is
    // n + AES_BLOCKSIZE bytes
    vchCiphertext.resize(vchPlaintext.size() + AES_BLOCKSIZE);
 
    AES256CBCEncrypt enc(chKey, chIV, true);
    size_t nLen = enc.Encrypt(&vchPlaintext[0], vchPlaintext.size(), &vchCiphertext[0]);
    if(nLen < vchPlaintext.size())
        return false;
    vchCiphertext.resize(nLen);
    return true;
}
 
bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext) const
{
    if (!fKeySet)
        return false;
 
    // plaintext will always be equal to or lesser than length of ciphertext
    int nLen = vchCiphertext.size();
    vchPlaintext.resize(nLen);
    AES256CBCDecrypt dec(chKey, chIV, true);
    nLen = dec.Decrypt(&vchCiphertext[0], vchCiphertext.size(), &vchPlaintext[0]);
    if(nLen == 0)
        return false;
    vchPlaintext.resize(nLen);
    return true;
}
 
bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial& vchPlaintext, const uint256& nIV, std::vector<unsigned char>& vchCiphertext)
{
    CCrypter cKeyCrypter;
    std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_IV_SIZE);
    if (!cKeyCrypter.SetKey(vMasterKey, chIV))
        return false;
    return cKeyCrypter.Encrypt(*((const CKeyingMaterial*)&vchPlaintext), vchCiphertext);
}
 
bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& vchPlaintext)
{
    CCrypter cKeyCrypter;
    std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_IV_SIZE);
    if (!cKeyCrypter.SetKey(vMasterKey, chIV))
        return false;
    return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
}
 
bool CCryptoKeyStore::SetCrypted()
{
    LOCK(cs_KeyStore);
    if (fUseCrypto)
        return true;
    if (!mapKeys.empty())
        return false;
    fUseCrypto = true;
    return true;
}
 
bool CCryptoKeyStore::AddKeyPubKey(const CKey& key, const CPubKey& pubkey)
{
    {
        LOCK(cs_KeyStore);
        if (!IsCrypted())
            return CBasicKeyStore::AddKeyPubKey(key, pubkey);
 
        if (IsLocked())
            return false;
 
        std::vector<unsigned char> vchCryptedSecret;
        CKeyingMaterial vchSecret(key.begin(), key.end());
        if (!EncryptSecret(vMasterKey, vchSecret, pubkey.GetHash(), vchCryptedSecret))
            return false;
 
        if (!AddCryptedKey(pubkey, vchCryptedSecret))
            return false;
    }
    return true;
}
 
 
bool CCryptoKeyStore::AddCryptedKey(const CPubKey& vchPubKey, const std::vector<unsigned char>& vchCryptedSecret)
{
    {
        LOCK(cs_KeyStore);
        if (!SetCrypted())
            return false;
 
        mapCryptedKeys[vchPubKey.GetID()] = make_pair(vchPubKey, vchCryptedSecret);
    }
    return true;
}
 
bool CCryptoKeyStore::GetKey(const CKeyID& address, CKey& keyOut) const
{
    {
        LOCK(cs_KeyStore);
        if (!IsCrypted())
            return CBasicKeyStore::GetKey(address, keyOut);
 
        CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
        if (mi != mapCryptedKeys.end()) {
            const CPubKey& vchPubKey = (*mi).second.first;
            const std::vector<unsigned char>& vchCryptedSecret = (*mi).second.second;
            CKeyingMaterial vchSecret;
            if (!DecryptSecret(vMasterKey, vchCryptedSecret, vchPubKey.GetHash(), vchSecret))
                return false;
            if (vchSecret.size() != 32)
                return false;
            keyOut.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());
            return true;
        }
    }
    return false;
}
 
bool CCryptoKeyStore::GetPubKey(const CKeyID& address, CPubKey& vchPubKeyOut) const
{
    {
        LOCK(cs_KeyStore);
        if (!IsCrypted())
            return CKeyStore::GetPubKey(address, vchPubKeyOut);
 
        CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
        if (mi != mapCryptedKeys.end()) {
            vchPubKeyOut = (*mi).second.first;
            return true;
        }
    }
    return false;
}
 
bool CCryptoKeyStore::EncryptKeys(CKeyingMaterial& vMasterKeyIn)
{
    {
        LOCK(cs_KeyStore);
        if (!mapCryptedKeys.empty() || IsCrypted())
            return false;
 
        fUseCrypto = true;
        for (KeyMap::value_type& mKey : mapKeys) {
            const CKey& key = mKey.second;
            CPubKey vchPubKey = key.GetPubKey();
            CKeyingMaterial vchSecret(key.begin(), key.end());
            std::vector<unsigned char> vchCryptedSecret;
            if (!EncryptSecret(vMasterKeyIn, vchSecret, vchPubKey.GetHash(), vchCryptedSecret))
                return false;
            if (!AddCryptedKey(vchPubKey, vchCryptedSecret))
                return false;
        }
        mapKeys.clear();
    }
    return true;
}
 
bool CCryptoKeyStore::EncryptHDChain(const CKeyingMaterial& vMasterKeyIn)
{
    // should call EncryptKeys first
    if (!IsCrypted())
        return false;
 
    if (!cryptedHDChain.IsNull())
        return true;
 
    if (cryptedHDChain.IsCrypted())
        return true;
 
    // make sure seed matches this chain
    if (hdChain.GetID() != hdChain.GetSeedHash())
        return false;
 
    std::vector<unsigned char> vchCryptedSeed;
    if (!EncryptSecret(vMasterKeyIn, hdChain.GetSeed(), hdChain.GetID(), vchCryptedSeed))
        return false;
 
    // hdChain.Debug(__func__);
    cryptedHDChain = hdChain;
    cryptedHDChain.SetCrypted(true);
 
    SecureVector vchSecureCryptedSeed(vchCryptedSeed.begin(), vchCryptedSeed.end());
    if (!cryptedHDChain.SetSeed(vchSecureCryptedSeed, false))
        return false;
 
    SecureVector vchMnemonic;
    SecureVector vchMnemonicPassphrase;
 
    // it's ok to have no mnemonic if wallet was initialized via hdseed
    if (hdChain.GetMnemonic(vchMnemonic, vchMnemonicPassphrase)) {
        std::vector<unsigned char> vchCryptedMnemonic;
        std::vector<unsigned char> vchCryptedMnemonicPassphrase;
 
        if (!vchMnemonic.empty() && !EncryptSecret(vMasterKeyIn, vchMnemonic, hdChain.GetID(), vchCryptedMnemonic))
            return false;
        if (!vchMnemonicPassphrase.empty() && !EncryptSecret(vMasterKeyIn, vchMnemonicPassphrase, hdChain.GetID(), vchCryptedMnemonicPassphrase))
            return false;
 
        SecureVector vchSecureCryptedMnemonic(vchCryptedMnemonic.begin(), vchCryptedMnemonic.end());
        SecureVector vchSecureCryptedMnemonicPassphrase(vchCryptedMnemonicPassphrase.begin(), vchCryptedMnemonicPassphrase.end());
        if (!cryptedHDChain.SetMnemonic(vchSecureCryptedMnemonic, vchSecureCryptedMnemonicPassphrase, false))
            return false;
    }
 
    if (!hdChain.SetNull())
        return false;
 
    return true;
}
 
bool CCryptoKeyStore::DecryptHDChain(CHDChain& hdChainRet) const
{
    if (!IsCrypted())
        return true;
    if (cryptedHDChain.IsNull())
        return false;
    if (!cryptedHDChain.IsCrypted())
        return false;
    SecureVector vchSecureSeed;
    SecureVector vchSecureCryptedSeed = cryptedHDChain.GetSeed();
    std::vector<unsigned char> vchCryptedSeed(vchSecureCryptedSeed.begin(), vchSecureCryptedSeed.end());
    if (!DecryptSecret(vMasterKey, vchCryptedSeed, cryptedHDChain.GetID(), vchSecureSeed))
        return false;
 
    hdChainRet = cryptedHDChain;
    if (!hdChainRet.SetSeed(vchSecureSeed, false))
        return false;
 
    // hash of decrypted seed must match chain id
    if (hdChainRet.GetSeedHash() != cryptedHDChain.GetID())
        return false;
 
    SecureVector vchSecureCryptedMnemonic;
    SecureVector vchSecureCryptedMnemonicPassphrase;
 
    // it's ok to have no mnemonic if wallet was initialized via hdseed
    if (cryptedHDChain.GetMnemonic(vchSecureCryptedMnemonic, vchSecureCryptedMnemonicPassphrase)) {
        SecureVector vchSecureMnemonic;
        SecureVector vchSecureMnemonicPassphrase;
 
        std::vector<unsigned char> vchCryptedMnemonic(vchSecureCryptedMnemonic.begin(), vchSecureCryptedMnemonic.end());
        std::vector<unsigned char> vchCryptedMnemonicPassphrase(vchSecureCryptedMnemonicPassphrase.begin(), vchSecureCryptedMnemonicPassphrase.end());
 
        if (!vchCryptedMnemonic.empty() && !DecryptSecret(vMasterKey, vchCryptedMnemonic, cryptedHDChain.GetID(), vchSecureMnemonic))
            return false;
        if (!vchCryptedMnemonicPassphrase.empty() && !DecryptSecret(vMasterKey, vchCryptedMnemonicPassphrase, cryptedHDChain.GetID(), vchSecureMnemonicPassphrase))
            return false;
        if (!hdChainRet.SetMnemonic(vchSecureMnemonic, vchSecureMnemonicPassphrase, false))
            return false;
    }
 
    hdChainRet.SetCrypted(false);
    // hdChainRet.Debug(__func__);
 
    return true;
}
 
bool CCryptoKeyStore::SetHDChain(const CHDChain& chain)
{
    if (IsCrypted())
        return false;
 
    if (chain.IsCrypted())
        return false;
 
    hdChain = chain;
    return true;
}
 
bool CCryptoKeyStore::SetCryptedHDChain(const CHDChain& chain)
{
    if (!SetCrypted())
        return false;
 
    if (!chain.IsCrypted())
        return false;
 
    cryptedHDChain = chain;
    return true;
}
 
bool CCryptoKeyStore::GetHDChain(CHDChain& hdChainRet) const
{
    if(IsCrypted()) {
        hdChainRet = cryptedHDChain;
        return !cryptedHDChain.IsNull();
    }
 
    hdChainRet = hdChain;
    return !hdChain.IsNull();
}