1 // Copyright (c) 2009-2012 The Bitcoin Developers
2 // Distributed under the MIT/X11 software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
7 #include "util.h" /* for SecureString */
10 const unsigned int WALLET_CRYPTO_KEY_SIZE = 32;
11 const unsigned int WALLET_CRYPTO_SALT_SIZE = 8;
14 Private key encryption is done based on a CMasterKey,
15 which holds a salt and random encryption key.
17 CMasterKeys are encrypted using AES-256-CBC using a key
18 derived using derivation method nDerivationMethod
19 (0 == EVP_sha512()) and derivation iterations nDeriveIterations.
20 vchOtherDerivationParameters is provided for alternative algorithms
21 which may require more parameters (such as scrypt).
23 Wallet Private Keys are then encrypted using AES-256-CBC
24 with the double-sha256 of the public key as the IV, and the
25 master key's key as the encryption key (see keystore.[ch]).
28 /** Master key for wallet encryption */
32 std::vector<unsigned char> vchCryptedKey;
33 std::vector<unsigned char> vchSalt;
36 unsigned int nDerivationMethod;
37 unsigned int nDeriveIterations;
38 // Use this for more parameters to key derivation,
39 // such as the various parameters to scrypt
40 std::vector<unsigned char> vchOtherDerivationParameters;
44 READWRITE(vchCryptedKey);
46 READWRITE(nDerivationMethod);
47 READWRITE(nDeriveIterations);
48 READWRITE(vchOtherDerivationParameters);
52 // 25000 rounds is just under 0.1 seconds on a 1.86 GHz Pentium M
53 // ie slightly lower than the lowest hardware we need bother supporting
54 nDeriveIterations = 25000;
55 nDerivationMethod = 0;
56 vchOtherDerivationParameters = std::vector<unsigned char>(0);
60 typedef std::vector<unsigned char, secure_allocator<unsigned char> > CKeyingMaterial;
62 /** Encryption/decryption context with key information */
66 unsigned char chKey[WALLET_CRYPTO_KEY_SIZE];
67 unsigned char chIV[WALLET_CRYPTO_KEY_SIZE];
71 bool SetKeyFromPassphrase(const SecureString &strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod);
72 bool Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext);
73 bool Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext);
74 bool SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV);
78 memset(&chKey, 0, sizeof chKey);
79 memset(&chIV, 0, sizeof chIV);
80 munlock(&chKey, sizeof chKey);
81 munlock(&chIV, sizeof chIV);
96 bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext);
97 bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char> &vchCiphertext, const uint256& nIV, CSecret &vchPlaintext);