diff options
Diffstat (limited to 'src/wallet/crypter.h')
| -rw-r--r-- | src/wallet/crypter.h | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/src/wallet/crypter.h b/src/wallet/crypter.h new file mode 100644 index 0000000000..32746b00df --- /dev/null +++ b/src/wallet/crypter.h @@ -0,0 +1,196 @@ +// 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 |