crypter.h

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// Copyright (c) 2009-2014 The Bitcoin developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#ifndef BITCOIN_CRYPTER_H
#define BITCOIN_CRYPTER_H
 
#include "allocators.h"
#include "keystore.h"
#include "serialize.h"
 
class uint256;
 
const unsigned int WALLET_CRYPTO_KEY_SIZE = 32;
const unsigned int WALLET_CRYPTO_SALT_SIZE = 8;
const unsigned int WALLET_CRYPTO_IV_SIZE = 16;
 
class CMasterKey
{
public:
    std::vector<unsigned char> vchCryptedKey;
    std::vector<unsigned char> vchSalt;
    unsigned int nDerivationMethod;
    unsigned int nDeriveIterations;
    std::vector<unsigned char> vchOtherDerivationParameters;
 
    ADD_SERIALIZE_METHODS;
 
    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion)
    {
        READWRITE(vchCryptedKey);
        READWRITE(vchSalt);
        READWRITE(nDerivationMethod);
        READWRITE(nDeriveIterations);
        READWRITE(vchOtherDerivationParameters);
    }
 
    CMasterKey()
    {
        // 25000 rounds is just under 0.1 seconds on a 1.86 GHz Pentium M
        // ie slightly lower than the lowest hardware we need bother supporting
        nDeriveIterations = 25000;
        nDerivationMethod = 0;
        vchOtherDerivationParameters = std::vector<unsigned char>(0);
    }
};
 
typedef std::vector<unsigned char, secure_allocator<unsigned char> > CKeyingMaterial;
 
namespace wallet_crypto
{
    class TestCrypter;
}
 
class CCrypter
{
    friend class wallet_crypto::TestCrypter; // for test access to chKey/chIV
private:
    unsigned char chKey[WALLET_CRYPTO_KEY_SIZE];
    unsigned char chIV[WALLET_CRYPTO_IV_SIZE];
    bool fKeySet;
 
    int BytesToKeySHA512AES(const std::vector<unsigned char>& chSalt, const SecureString& strKeyData, int count, unsigned char *key,unsigned char *iv) const;
 
public:
    bool SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod);
    bool Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char>& vchCiphertext) const;
    bool Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext) const;
    bool SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV);
 
    void CleanKey()
    {
        memory_cleanse(chKey, sizeof(chKey));
        memory_cleanse(chIV, sizeof(chIV));
        fKeySet = false;
    }
 
    CCrypter()
    {
        fKeySet = false;
 
        // Try to keep the key data out of swap (and be a bit over-careful to keep the IV that we don't even use out of swap)
        // Note that this does nothing about suspend-to-disk (which will put all our key data on disk)
        // Note as well that at no point in this program is any attempt made to prevent stealing of keys by reading the memory of the running process.
        LockedPageManager::Instance().LockRange(&chKey[0], sizeof chKey);
        LockedPageManager::Instance().LockRange(&chIV[0], sizeof chIV);
    }
 
    ~CCrypter()
    {
        CleanKey();
 
        LockedPageManager::Instance().UnlockRange(&chKey[0], sizeof chKey);
        LockedPageManager::Instance().UnlockRange(&chIV[0], sizeof chIV);
    }
};
 
bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial& vchPlaintext, const uint256& nIV, std::vector<unsigned char>& vchCiphertext);
bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& vchPlaintext);
 
 
class CCryptoKeyStore : public CBasicKeyStore
{
private:
    bool fUseCrypto;
 
protected:
    // TODO: In the future, move this variable to the wallet class directly following upstream's structure.
    CKeyingMaterial vMasterKey;
 
    bool SetCrypted();
 
    bool EncryptKeys(CKeyingMaterial& vMasterKeyIn);
    bool EncryptHDChain(const CKeyingMaterial& vMasterKeyIn);
    bool DecryptHDChain(CHDChain& hdChainRet) const;
    bool SetHDChain(const CHDChain& chain);
    bool SetCryptedHDChain(const CHDChain& chain);
    bool GetHDChain(CHDChain& hdChainRet) const;
 
    CryptedKeyMap mapCryptedKeys;
    CHDChain cryptedHDChain;
 
public:
    CCryptoKeyStore() : fUseCrypto(false) { }
 
    bool IsCrypted() const
    {
        return fUseCrypto;
    }
 
    bool IsLocked() const
    {
        if (!IsCrypted())
            return false;
        bool result;
        {
            LOCK(cs_KeyStore);
            result = vMasterKey.empty();
        }
        return result;
    }
 
    virtual bool AddCryptedKey(const CPubKey& vchPubKey, const std::vector<unsigned char>& vchCryptedSecret);
    bool AddKeyPubKey(const CKey& key, const CPubKey& pubkey);
    bool HaveKey(const CKeyID& address) const
    {
        {
            LOCK(cs_KeyStore);
            if (!IsCrypted())
                return CBasicKeyStore::HaveKey(address);
            return mapCryptedKeys.count(address) > 0;
        }
        return false;
    }
    bool GetKey(const CKeyID& address, CKey& keyOut) const;
    bool GetPubKey(const CKeyID& address, CPubKey& vchPubKeyOut) const;
    void GetKeys(std::set<CKeyID>& setAddress) const
    {
        if (!IsCrypted()) {
            CBasicKeyStore::GetKeys(setAddress);
            return;
        }
        setAddress.clear();
        CryptedKeyMap::const_iterator mi = mapCryptedKeys.begin();
        while (mi != mapCryptedKeys.end()) {
            setAddress.insert((*mi).first);
            mi++;
        }
    }
 
    boost::signals2::signal<void(CCryptoKeyStore* wallet)> NotifyStatusChanged;
};
 
#endif // BITCOIN_CRYPTER_H