commit e9707e8ec7ef058c0ff08b6b454f0393843c5ff0
Author: Jeff Garzik <jeff@garzik.org>
Date:   Sat Mar 26 16:50:30 2011 -0400

    Add wallet privkey encryption, and use it for all new keys

diff --git a/crypter.h b/crypter.h
new file mode 100644
index 0000000..c119dc9
--- /dev/null
+++ b/crypter.h
@@ -0,0 +1,64 @@
+#ifndef __CRYPTER_H__
+#define __CRYPTER_H__
+
+class CCrypter
+{
+protected:
+    EVP_CIPHER_CTX e_ctx;
+    EVP_CIPHER_CTX d_ctx;
+
+public:
+    bool SetKey(const unsigned char *keyData, int keyData_len,
+                const unsigned char *salt)
+    {
+        int nrounds = 1000;
+        unsigned char key[32], iv[32];
+  
+        int i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha256(), salt,
+                               keyData, keyData_len, nrounds, key, iv);
+        if (i != 32)
+            return false;
+
+        EVP_CIPHER_CTX_init(&e_ctx);
+        EVP_EncryptInit_ex(&e_ctx, EVP_aes_256_cbc(), NULL, key, iv);
+        EVP_CIPHER_CTX_init(&d_ctx);
+        EVP_DecryptInit_ex(&d_ctx, EVP_aes_256_cbc(), NULL, key, iv);
+
+        return true;
+    }
+
+    vector<unsigned char> Encrypt(vector<unsigned char> vchPlaintext)
+    {
+      // max ciphertext len for a n bytes of plaintext is
+      // n + AES_BLOCK_SIZE - 1 bytes
+      int len = vchPlaintext.size();
+      int c_len = len + AES_BLOCK_SIZE, f_len = 0;
+      vector<unsigned char> vchCiphertext(c_len);
+
+      EVP_EncryptInit_ex(&e_ctx, NULL, NULL, NULL, NULL);
+      EVP_EncryptUpdate(&e_ctx, &vchCiphertext[0], &c_len,
+                        &vchPlaintext[0], len);
+      EVP_EncryptFinal_ex(&e_ctx, (&vchCiphertext[0])+c_len, &f_len);
+
+      vchCiphertext.resize(c_len + f_len);
+      return vchCiphertext;
+    }
+
+    vector<unsigned char> Decrypt(vector<unsigned char> vchCiphertext)
+    {
+      // plaintext will always be equal to or lesser than length of ciphertext
+      int len = vchCiphertext.size();
+      int p_len = len, f_len = 0;
+      vector<unsigned char> vchPlaintext(p_len);
+  
+      EVP_DecryptInit_ex(&d_ctx, NULL, NULL, NULL, NULL);
+      EVP_DecryptUpdate(&d_ctx, &vchPlaintext[0], &p_len,
+                        &vchCiphertext[0], len);
+      EVP_DecryptFinal_ex(&d_ctx, (&vchPlaintext[0])+p_len, &f_len);
+
+      vchPlaintext.resize(p_len + f_len);
+      return vchPlaintext;
+    }
+};
+
+#endif /* __CRYPTER_H__ */
diff --git a/db.cpp b/db.cpp
index aaa997b..6e5c31a 100644
--- a/db.cpp
+++ b/db.cpp
@@ -744,6 +744,25 @@ bool CWalletDB::LoadWallet()
                 if (nNumber > nAccountingEntryNumber)
                     nAccountingEntryNumber = nNumber;
             }
+            else if (strType == "ekey")
+            {
+                vector<unsigned char> vchPubKey;
+                ssKey >> vchPubKey;
+
+                vector<unsigned char> vchCiphertext;
+                ssKey >> vchCiphertext;
+
+                vector<unsigned char> vchPlaintext;
+                vchPlaintext = cWalletCrypter.Decrypt(vchCiphertext);
+
+                CWalletKey wkey;
+                wkey.vchPrivKey.resize(vchPlaintext.size());
+                memcpy(&wkey.vchPrivKey[0], &vchPlaintext[0],
+                       vchPlaintext.size());
+
+                mapKeys[vchPubKey] = wkey.vchPrivKey;
+                mapPubKeys[Hash160(vchPubKey)] = vchPubKey;
+            }
             else if (strType == "key" || strType == "wkey")
             {
                 vector<unsigned char> vchPubKey;
diff --git a/db.h b/db.h
index c9c40d5..9d8ba80 100644
--- a/db.h
+++ b/db.h
@@ -399,10 +399,11 @@ public:
         return Read(make_pair(string("key"), vchPubKey), vchPrivKey);
     }
 
-    bool WriteKey(const vector<unsigned char>& vchPubKey, const CPrivKey& vchPrivKey)
+    bool WriteKey(const vector<unsigned char>& vchPubKey,
+                  const vector<unsigned char>& vchCiphertext)
     {
         nWalletDBUpdated++;
-        return Write(make_pair(string("key"), vchPubKey), vchPrivKey, false);
+        return Write(make_pair(string("ekey"), vchPubKey), vchCiphertext,false);
     }
 
     bool ReadDefaultKey(vector<unsigned char>& vchPubKey)
diff --git a/headers.h b/headers.h
index 6a08cb7..964fa14 100644
--- a/headers.h
+++ b/headers.h
@@ -39,6 +39,7 @@
 #include <openssl/evp.h>
 #include <openssl/rand.h>
 #include <openssl/sha.h>
+#include <openssl/aes.h>
 #include <openssl/ripemd.h>
 #include <db_cxx.h>
 #include <stdio.h>
@@ -117,6 +118,7 @@ using namespace boost;
 #include "uint256.h"
 #include "util.h"
 #include "key.h"
+#include "crypter.h"
 #include "bignum.h"
 #include "base58.h"
 #include "script.h"
diff --git a/init.cpp b/init.cpp
index 8c70ba2..0647d8f 100644
--- a/init.cpp
+++ b/init.cpp
@@ -326,6 +326,36 @@ bool AppInit2(int argc, char* argv[])
         }
     }
 
+    // obtain wallet encrypt/decrypt key, from passphrase
+    string strWalletPass = getenv("WALLET_PASSPHRASE");
+
+#ifdef GUI
+    if (!strWalletPass.size()) {
+        strWalletPass = wxGetPasswordFromUser(
+                _("Input passphrase to decrypt wallet"), _("Password"));
+    }
+#endif
+    if (!strWalletPass.size()) {
+#ifdef GUI
+        wxMessageBox(_("Wallet decryption password not supplied"), "Bitcoin");
+#else
+        fprintf(stderr, "Wallet decryption password not supplied\n");
+#endif
+        return false;
+    }
+
+    string strSalt = "bitcoin is fun!";
+    if (!cWalletCrypter.SetKey((const unsigned char *)strWalletPass.c_str(),
+                               strWalletPass.size(),
+                               (const unsigned char *)strSalt.c_str())) {
+#ifdef GUI
+        wxMessageBox(_("Wallet decryption setup failed"), "Bitcoin");
+#else
+        fprintf(stderr, "Wallet decryption setup failed\n");
+#endif
+        return false;
+    }
+
     //
     // Load data files
     //
diff --git a/main.cpp b/main.cpp
index bfc45af..f43fe9c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -41,6 +41,7 @@ map<uint256, CWalletTx> mapWallet;
 vector<uint256> vWalletUpdated;
 CCriticalSection cs_mapWallet;
 
+CCrypter cWalletCrypter;
 map<vector<unsigned char>, CPrivKey> mapKeys;
 map<uint160, vector<unsigned char> > mapPubKeys;
 CCriticalSection cs_mapKeys;
@@ -83,7 +84,14 @@ bool AddKey(const CKey& key)
         mapKeys[key.GetPubKey()] = key.GetPrivKey();
         mapPubKeys[Hash160(key.GetPubKey())] = key.GetPubKey();
     }
-    return CWalletDB().WriteKey(key.GetPubKey(), key.GetPrivKey());
+
+    CPrivKey privKey = key.GetPrivKey();
+    vector<unsigned char> vchPlaintext(privKey.size());
+    memcpy(&vchPlaintext[0], &privKey[0], privKey.size());
+
+    vector<unsigned char> vchCiphertext;
+    vchCiphertext = cWalletCrypter.Encrypt(vchPlaintext);
+    return CWalletDB().WriteKey(key.GetPubKey(), vchCiphertext);
 }
 
 vector<unsigned char> GenerateNewKey()
diff --git a/main.h b/main.h
index e9d0c00..f104d93 100644
--- a/main.h
+++ b/main.h
@@ -46,6 +46,7 @@ extern CCriticalSection cs_mapAddressBook;
 extern vector<unsigned char> vchDefaultKey;
 extern double dHashesPerSec;
 extern int64 nHPSTimerStart;
+extern CCrypter cWalletCrypter;
 
 // Settings
 extern int fGenerateBitcoins;