crypter.h

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// Copyright (c) 2009-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#ifndef BITCOIN_WALLET_CRYPTER_H
#define BITCOIN_WALLET_CRYPTER_H
 
#include <script/signingprovider.h>
#include <serialize.h>
#include <support/allocators/secure.h>
 
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<uint8_t> vchCryptedKey;
    std::vector<uint8_t> vchSalt;
    unsigned int nDerivationMethod;
    unsigned int nDeriveIterations;
    std::vector<uint8_t> vchOtherDerivationParameters;
 
    SERIALIZE_METHODS(CMasterKey, obj) {
        READWRITE(obj.vchCryptedKey, obj.vchSalt, obj.nDerivationMethod,
                  obj.nDeriveIterations, obj.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<uint8_t>(0);
    }
};
 
typedef std::vector<uint8_t, secure_allocator<uint8_t>> CKeyingMaterial;
 
namespace wallet_crypto_tests {
class TestCrypter;
}
 
class CCrypter {
    // for test access to chKey/chIV
    friend class wallet_crypto_tests::TestCrypter;
 
private:
    std::vector<uint8_t, secure_allocator<uint8_t>> vchKey;
    std::vector<uint8_t, secure_allocator<uint8_t>> vchIV;
    bool fKeySet;
 
    int BytesToKeySHA512AES(const std::vector<uint8_t> &chSalt,
                            const SecureString &strKeyData, int count,
                            uint8_t *key, uint8_t *iv) const;
 
public:
    bool SetKeyFromPassphrase(const SecureString &strKeyData,
                              const std::vector<uint8_t> &chSalt,
                              const unsigned int nRounds,
                              const unsigned int nDerivationMethod);
    bool Encrypt(const CKeyingMaterial &vchPlaintext,
                 std::vector<uint8_t> &vchCiphertext) const;
    bool Decrypt(const std::vector<uint8_t> &vchCiphertext,
                 CKeyingMaterial &vchPlaintext) const;
    bool SetKey(const CKeyingMaterial &chNewKey,
                const std::vector<uint8_t> &chNewIV);
 
    void CleanKey() {
        memory_cleanse(vchKey.data(), vchKey.size());
        memory_cleanse(vchIV.data(), vchIV.size());
        fKeySet = false;
    }
 
    CCrypter() {
        fKeySet = false;
        vchKey.resize(WALLET_CRYPTO_KEY_SIZE);
        vchIV.resize(WALLET_CRYPTO_IV_SIZE);
    }
 
    ~CCrypter() { CleanKey(); }
};
 
bool EncryptSecret(const CKeyingMaterial &vMasterKey,
                   const CKeyingMaterial &vchPlaintext, const uint256 &nIV,
                   std::vector<uint8_t> &vchCiphertext);
bool DecryptSecret(const CKeyingMaterial &vMasterKey,
                   const std::vector<uint8_t> &vchCiphertext,
                   const uint256 &nIV, CKeyingMaterial &vchPlaintext);
bool DecryptKey(const CKeyingMaterial &vMasterKey,
                const std::vector<uint8_t> &vchCryptedSecret,
                const CPubKey &vchPubKey, CKey &key);
 
#endif // BITCOIN_WALLET_CRYPTER_H