1 files changed, 132 insertions, 0 deletions
diff --git a/src/crypter.cpp b/src/crypter.cpp
new file mode 100644
index 0000000000..9a8e6ca89a
--- /dev/null
+++ b/src/crypter.cpp
@@ -0,0 +1,132 @@
+// 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.
+
+#include <openssl/aes.h>
+#include <openssl/evp.h>
+#include <vector>
+#include <string>
+#include "headers.h"
+#ifdef __WXMSW__
+#include <windows.h>
+#endif
+
+#include "crypter.h"
+#include "main.h"
+#include "util.h"
+
+bool CCrypter::SetKeyFromPassphrase(const std::string& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
+{
+    if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
+        return false;
+
+    // Try to keep the keydata 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.  
+    mlock(&chKey[0], sizeof chKey);
+    mlock(&chIV[0], sizeof chIV);
+
+    int i = 0;
+    if (nDerivationMethod == 0)
+        i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha512(), &chSalt[0],
+                          (unsigned char *)&strKeyData[0], strKeyData.size(), nRounds, chKey, chIV);
+
+    if (i != WALLET_CRYPTO_KEY_SIZE)
+    {
+        memset(&chKey, 0, sizeof chKey);
+        memset(&chIV, 0, sizeof chIV);
+        return false;
+    }
+
+    fKeySet = true;
+    return true;
+}
+
+bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
+{
+    if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_KEY_SIZE)
+        return false;
+
+    // Try to keep the keydata 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.  
+    mlock(&chKey[0], sizeof chKey);
+    mlock(&chIV[0], sizeof chIV);
+
+    memcpy(&chKey[0], &chNewKey[0], sizeof chKey);
+    memcpy(&chIV[0], &chNewIV[0], sizeof chIV);
+
+    fKeySet = true;
+    return true;
+}
+
+bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext)
+{
+    if (!fKeySet)
+        return false;
+
+    // max ciphertext len for a n bytes of plaintext is
+    // n + AES_BLOCK_SIZE - 1 bytes
+    int nLen = vchPlaintext.size();
+    int nCLen = nLen + AES_BLOCK_SIZE, nFLen = 0;
+    vchCiphertext = std::vector<unsigned char> (nCLen);
+
+    EVP_CIPHER_CTX ctx;
+
+    EVP_CIPHER_CTX_init(&ctx);
+    EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
+
+    EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen);
+    EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0])+nCLen, &nFLen);
+
+    EVP_CIPHER_CTX_cleanup(&ctx);
+
+    vchCiphertext.resize(nCLen + nFLen);
+    return true;
+}
+
+bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext)
+{
+    if (!fKeySet)
+        return false;
+
+    // plaintext will always be equal to or lesser than length of ciphertext
+    int nLen = vchCiphertext.size();
+    int nPLen = nLen, nFLen = 0;
+
+    vchPlaintext = CKeyingMaterial(nPLen);
+
+    EVP_CIPHER_CTX ctx;
+
+    EVP_CIPHER_CTX_init(&ctx);
+    EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
+
+    EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen);
+    EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0])+nPLen, &nFLen);
+
+    EVP_CIPHER_CTX_cleanup(&ctx);
+
+    vchPlaintext.resize(nPLen + nFLen);
+    return true;
+}
+
+
+bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext)
+{
+    CCrypter cKeyCrypter;
+    std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
+    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
+    if(!cKeyCrypter.SetKey(vMasterKey, chIV))
+        return false;
+    return cKeyCrypter.Encrypt((CKeyingMaterial)vchPlaintext, vchCiphertext);
+}
+
+bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CSecret& vchPlaintext)
+{
+    CCrypter cKeyCrypter;
+    std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
+    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
+    if(!cKeyCrypter.SetKey(vMasterKey, chIV))
+        return false;
+    return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
+}