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107 lines
3.9 KiB
107 lines
3.9 KiB
// Copyright (c) 2009-2012 The Bitcoin Developers |
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// Distributed under the MIT/X11 software license, see the accompanying |
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// file COPYING or http://www.opensource.org/licenses/mit-license.php. |
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#ifndef __CRYPTER_H__ |
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#define __CRYPTER_H__ |
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#include "allocators.h" /* for SecureString */ |
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#include "key.h" |
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#include "serialize.h" |
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const unsigned int WALLET_CRYPTO_KEY_SIZE = 32; |
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const unsigned int WALLET_CRYPTO_SALT_SIZE = 8; |
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/* |
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Private key encryption is done based on a CMasterKey, |
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which holds a salt and random encryption key. |
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CMasterKeys are encrypted using AES-256-CBC using a key |
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derived using derivation method nDerivationMethod |
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(0 == EVP_sha512()) and derivation iterations nDeriveIterations. |
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vchOtherDerivationParameters is provided for alternative algorithms |
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which may require more parameters (such as scrypt). |
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Wallet Private Keys are then encrypted using AES-256-CBC |
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with the double-sha256 of the public key as the IV, and the |
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master key's key as the encryption key (see keystore.[ch]). |
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*/ |
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/** Master key for wallet encryption */ |
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class CMasterKey |
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{ |
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public: |
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std::vector<unsigned char> vchCryptedKey; |
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std::vector<unsigned char> vchSalt; |
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// 0 = EVP_sha512() |
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// 1 = scrypt() |
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unsigned int nDerivationMethod; |
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unsigned int nDeriveIterations; |
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// Use this for more parameters to key derivation, |
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// such as the various parameters to scrypt |
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std::vector<unsigned char> vchOtherDerivationParameters; |
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IMPLEMENT_SERIALIZE |
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( |
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READWRITE(vchCryptedKey); |
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READWRITE(vchSalt); |
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READWRITE(nDerivationMethod); |
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READWRITE(nDeriveIterations); |
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READWRITE(vchOtherDerivationParameters); |
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) |
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CMasterKey() |
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{ |
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// 25000 rounds is just under 0.1 seconds on a 1.86 GHz Pentium M |
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// ie slightly lower than the lowest hardware we need bother supporting |
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nDeriveIterations = 25000; |
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nDerivationMethod = 0; |
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vchOtherDerivationParameters = std::vector<unsigned char>(0); |
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} |
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}; |
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typedef std::vector<unsigned char, secure_allocator<unsigned char> > CKeyingMaterial; |
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/** Encryption/decryption context with key information */ |
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class CCrypter |
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{ |
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private: |
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unsigned char chKey[WALLET_CRYPTO_KEY_SIZE]; |
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unsigned char chIV[WALLET_CRYPTO_KEY_SIZE]; |
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bool fKeySet; |
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public: |
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bool SetKeyFromPassphrase(const SecureString &strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod); |
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bool Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext); |
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bool Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext); |
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bool SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV); |
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void CleanKey() |
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{ |
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OPENSSL_cleanse(chKey, sizeof(chKey)); |
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OPENSSL_cleanse(chIV, sizeof(chIV)); |
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fKeySet = false; |
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} |
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CCrypter() |
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{ |
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fKeySet = false; |
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// 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) |
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// Note that this does nothing about suspend-to-disk (which will put all our key data on disk) |
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// 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. |
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LockedPageManager::instance.LockRange(&chKey[0], sizeof chKey); |
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LockedPageManager::instance.LockRange(&chIV[0], sizeof chIV); |
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} |
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~CCrypter() |
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{ |
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CleanKey(); |
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LockedPageManager::instance.UnlockRange(&chKey[0], sizeof chKey); |
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LockedPageManager::instance.UnlockRange(&chIV[0], sizeof chIV); |
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} |
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}; |
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bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext); |
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bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char> &vchCiphertext, const uint256& nIV, CSecret &vchPlaintext); |
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#endif
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