Line data    Source code

       1             : // Copyright (c) 2009-2021 The Bitcoin Core developers
       2             : // Distributed under the MIT software license, see the accompanying
       3             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4             : 
       5             : #ifndef BITCOIN_WALLET_CRYPTER_H
       6             : #define BITCOIN_WALLET_CRYPTER_H
       7             : 
       8             : #include <serialize.h>
       9             : #include <support/allocators/secure.h>
      10             : #include <script/signingprovider.h>
      11             : 
      12             : 
      13             : namespace wallet {
      14             : const unsigned int WALLET_CRYPTO_KEY_SIZE = 32;
      15             : const unsigned int WALLET_CRYPTO_SALT_SIZE = 8;
      16             : const unsigned int WALLET_CRYPTO_IV_SIZE = 16;
      17             : 
      18             : /**
      19             :  * Private key encryption is done based on a CMasterKey,
      20             :  * which holds a salt and random encryption key.
      21             :  *
      22             :  * CMasterKeys are encrypted using AES-256-CBC using a key
      23             :  * derived using derivation method nDerivationMethod
      24             :  * (0 == EVP_sha512()) and derivation iterations nDeriveIterations.
      25             :  * vchOtherDerivationParameters is provided for alternative algorithms
      26             :  * which may require more parameters (such as scrypt).
      27             :  *
      28             :  * Wallet Private Keys are then encrypted using AES-256-CBC
      29             :  * with the double-sha256 of the public key as the IV, and the
      30             :  * master key's key as the encryption key (see keystore.[ch]).
      31             :  */
      32             : 
      33             : /** Master key for wallet encryption */
      34             : class CMasterKey
      35             : {
      36             : public:
      37             :     std::vector<unsigned char> vchCryptedKey;
      38             :     std::vector<unsigned char> vchSalt;
      39             :     //! 0 = EVP_sha512()
      40             :     //! 1 = scrypt()
      41             :     unsigned int nDerivationMethod;
      42             :     unsigned int nDeriveIterations;
      43             :     //! Use this for more parameters to key derivation,
      44             :     //! such as the various parameters to scrypt
      45             :     std::vector<unsigned char> vchOtherDerivationParameters;
      46             : 
      47           0 :     SERIALIZE_METHODS(CMasterKey, obj)
      48             :     {
      49           0 :         READWRITE(obj.vchCryptedKey, obj.vchSalt, obj.nDerivationMethod, obj.nDeriveIterations, obj.vchOtherDerivationParameters);
      50           0 :     }
      51             : 
      52           0 :     CMasterKey()
      53             :     {
      54             :         // 25000 rounds is just under 0.1 seconds on a 1.86 GHz Pentium M
      55             :         // ie slightly lower than the lowest hardware we need bother supporting
      56           0 :         nDeriveIterations = 25000;
      57           0 :         nDerivationMethod = 0;
      58           0 :         vchOtherDerivationParameters = std::vector<unsigned char>(0);
      59           0 :     }
      60             : };
      61             : 
      62             : typedef std::vector<unsigned char, secure_allocator<unsigned char> > CKeyingMaterial;
      63             : 
      64             : namespace wallet_crypto_tests
      65             : {
      66             :     class TestCrypter;
      67             : }
      68             : 
      69             : /** Encryption/decryption context with key information */
      70             : class CCrypter
      71             : {
      72             : friend class wallet_crypto_tests::TestCrypter; // for test access to chKey/chIV
      73             : private:
      74             :     std::vector<unsigned char, secure_allocator<unsigned char>> vchKey;
      75             :     std::vector<unsigned char, secure_allocator<unsigned char>> vchIV;
      76             :     bool fKeySet;
      77             : 
      78             :     int BytesToKeySHA512AES(const std::vector<unsigned char>& chSalt, const SecureString& strKeyData, int count, unsigned char *key,unsigned char *iv) const;
      79             : 
      80             : public:
      81             :     bool SetKeyFromPassphrase(const SecureString &strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod);
      82             :     bool Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext) const;
      83             :     bool Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext) const;
      84             :     bool SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV);
      85             : 
      86           0 :     void CleanKey()
      87             :     {
      88           0 :         memory_cleanse(vchKey.data(), vchKey.size());
      89           0 :         memory_cleanse(vchIV.data(), vchIV.size());
      90           0 :         fKeySet = false;
      91           0 :     }
      92             : 
      93           0 :     CCrypter()
      94             :     {
      95           0 :         fKeySet = false;
      96           0 :         vchKey.resize(WALLET_CRYPTO_KEY_SIZE);
      97           0 :         vchIV.resize(WALLET_CRYPTO_IV_SIZE);
      98           0 :     }
      99             : 
     100           0 :     ~CCrypter()
     101             :     {
     102           0 :         CleanKey();
     103           0 :     }
     104             : };
     105             : 
     106             : bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext);
     107             : bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& vchPlaintext);
     108             : bool DecryptKey(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCryptedSecret, const CPubKey& vchPubKey, CKey& key);
     109             : } // namespace wallet
     110             : 
     111             : #endif // BITCOIN_WALLET_CRYPTER_H