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+// Copyright (c) 2009-2014 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_CRYPTER_H
+#define BITCOIN_CRYPTER_H
+
+#include "keystore.h"
+#include "serialize.h"
+#include "support/allocators/secure.h"
+
+class uint256;
+
+const unsigned int WALLET_CRYPTO_KEY_SIZE = 32;
+const unsigned int WALLET_CRYPTO_SALT_SIZE = 8;
+
+/**
+ * Private key encryption is done based on a CMasterKey,
+ * which holds a salt and random encryption key.
+ *
+ * CMasterKeys are encrypted using AES-256-CBC using a key
+ * derived using derivation method nDerivationMethod
+ * (0 == EVP_sha512()) and derivation iterations nDeriveIterations.
+ * vchOtherDerivationParameters is provided for alternative algorithms
+ * which may require more parameters (such as scrypt).
+ *
+ * Wallet Private Keys are then encrypted using AES-256-CBC
+ * with the double-sha256 of the public key as the IV, and the
+ * master key's key as the encryption key (see keystore.[ch]).
+ */
+
+/** Master key for wallet encryption */
+class CMasterKey
+{
+public:
+ std::vector<unsigned char> vchCryptedKey;
+ std::vector<unsigned char> vchSalt;
+ //! 0 = EVP_sha512()
+ //! 1 = scrypt()
+ unsigned int nDerivationMethod;
+ unsigned int nDeriveIterations;
+ //! Use this for more parameters to key derivation,
+ //! such as the various parameters to scrypt
+ 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;
+
+/** Encryption/decryption context with key information */
+class CCrypter
+{
+private:
+ unsigned char chKey[WALLET_CRYPTO_KEY_SIZE];
+ unsigned char chIV[WALLET_CRYPTO_KEY_SIZE];
+ bool fKeySet;
+
+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);
+ bool Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext);
+ 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);
+ }
+};
+
+/** Keystore which keeps the private keys encrypted.
+ * It derives from the basic key store, which is used if no encryption is active.
+ */
+class CCryptoKeyStore : public CBasicKeyStore
+{
+private:
+ CryptedKeyMap mapCryptedKeys;
+
+ CKeyingMaterial vMasterKey;
+
+ //! if fUseCrypto is true, mapKeys must be empty
+ //! if fUseCrypto is false, vMasterKey must be empty
+ bool fUseCrypto;
+
+ //! keeps track of whether Unlock has run a thorough check before
+ bool fDecryptionThoroughlyChecked;
+
+protected:
+ bool SetCrypted();
+
+ //! will encrypt previously unencrypted keys
+ bool EncryptKeys(CKeyingMaterial& vMasterKeyIn);
+
+ bool Unlock(const CKeyingMaterial& vMasterKeyIn);
+
+public:
+ CCryptoKeyStore() : fUseCrypto(false), fDecryptionThoroughlyChecked(false)
+ {
+ }
+
+ bool IsCrypted() const
+ {
+ return fUseCrypto;
+ }
+
+ bool IsLocked() const
+ {
+ if (!IsCrypted())
+ return false;
+ bool result;
+ {
+ LOCK(cs_KeyStore);
+ result = vMasterKey.empty();
+ }
+ return result;
+ }
+
+ bool Lock();
+
+ 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++;
+ }
+ }
+
+ /**
+ * Wallet status (encrypted, locked) changed.
+ * Note: Called without locks held.
+ */
+ boost::signals2::signal<void (CCryptoKeyStore* wallet)> NotifyStatusChanged;
+};
+
+#endif // BITCOIN_CRYPTER_H