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108 lines
3.9 KiB
108 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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memset(&chKey, 0, sizeof chKey);
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memset(&chIV, 0, 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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