wallet: move crypter to wallet

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