1 files changed, 96 insertions, 0 deletions
diff --git a/src/crypter.h b/src/crypter.h
new file mode 100644
index 0000000000..5b95ea415e
--- /dev/null
+++ b/src/crypter.h
@@ -0,0 +1,96 @@
+// Copyright (c) 2011 The Bitcoin Developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+#ifndef __CRYPTER_H__
+#define __CRYPTER_H__
+
+#include "key.h"
+
+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 is 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 private key as the IV, and the
+master key's key as the encryption key.
+*/
+
+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;
+
+    IMPLEMENT_SERIALIZE
+    (
+        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;
+
+class CCrypter
+{
+private:
+    unsigned char chKey[WALLET_CRYPTO_KEY_SIZE];
+    unsigned char chIV[WALLET_CRYPTO_KEY_SIZE];
+    bool fKeySet;
+
+public:
+    bool SetKeyFromPassphrase(const std::string &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()
+    {
+        memset(&chKey, 0, sizeof chKey);
+        memset(&chIV, 0, sizeof chIV);
+        munlock(&chKey, sizeof chKey);
+        munlock(&chIV, sizeof chIV);
+        fKeySet = false;
+    }
+
+    CCrypter()
+    {
+        fKeySet = false;
+    }
+
+    ~CCrypter()
+    {
+        CleanKey();
+    }
+};
+
+bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext);
+bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char> &vchCiphertext, const uint256& nIV, CSecret &vchPlaintext);
+
+#endif