text: // Copyright (c) 2009-2013 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 "crypter.h"
  
  #include "script/script.h"
  #include "script/standard.h"
  #include "util.h"
  
  #include <boost/foreach.hpp>
  #include <openssl/aes.h>
  #include <openssl/evp.h>
  #include <string>
  #include <vector>
  
  bool CCrypter::SetKeyFromPassphrase(const SecureString& 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;
  
      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 != (int)WALLET_CRYPTO_KEY_SIZE) {
          OPENSSL_cleanse(chKey, sizeof(chKey));
          OPENSSL_cleanse(chIV, 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;
  
      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;
  
      bool fOk = true;
  
      EVP_CIPHER_CTX_init(&ctx);
      if (fOk) fOk = EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV) != 0;
      if (fOk) fOk = EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen) != 0;
      if (fOk) fOk = EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0]) + nCLen, &nFLen) != 0;
      EVP_CIPHER_CTX_cleanup(&ctx);
  
      if (!fOk) return false;
  
      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;
  
      bool fOk = true;
  
      EVP_CIPHER_CTX_init(&ctx);
      if (fOk) fOk = EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV) != 0;
      if (fOk) fOk = EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen) != 0;
      if (fOk) fOk = EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0]) + nPLen, &nFLen) != 0;
      EVP_CIPHER_CTX_cleanup(&ctx);
  
      if (!fOk) return false;
  
      vchPlaintext.resize(nPLen + nFLen);
      return true;
  }
  
  
  bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial& 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(*((const CKeyingMaterial*)&vchPlaintext), vchCiphertext);
  }
  
  
  // General secure AES 256 CBC encryption routine
  bool EncryptAES256(const SecureString& sKey, const SecureString& sPlaintext, const std::string& sIV, std::string& sCiphertext)
  {
      // max ciphertext len for a n bytes of plaintext is
      // n + AES_BLOCK_SIZE - 1 bytes
      int nLen = sPlaintext.size();
      int nCLen = nLen + AES_BLOCK_SIZE;
      int nFLen = 0;
  
      // Verify key sizes
      if (sKey.size() != 32 || sIV.size() != AES_BLOCK_SIZE) {
          LogPrintf("crypter EncryptAES256 - Invalid key or block size: Key: %d sIV:%d\n", sKey.size(), sIV.size());
          return false;
      }
  
      // Prepare output buffer
      sCiphertext.resize(nCLen);
  
      // Perform the encryption
      EVP_CIPHER_CTX ctx;
  
      bool fOk = true;
  
      EVP_CIPHER_CTX_init(&ctx);
      if (fOk) fOk = EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, (const unsigned char*)&sKey[0], (const unsigned char*)&sIV[0]);
      if (fOk) fOk = EVP_EncryptUpdate(&ctx, (unsigned char*)&sCiphertext[0], &nCLen, (const unsigned char*)&sPlaintext[0], nLen);
      if (fOk) fOk = EVP_EncryptFinal_ex(&ctx, (unsigned char*)(&sCiphertext[0]) + nCLen, &nFLen);
      EVP_CIPHER_CTX_cleanup(&ctx);
  
      if (!fOk) return false;
  
      sCiphertext.resize(nCLen + nFLen);
      return true;
  }
  
  
  bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& 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));
  }
  
  bool DecryptAES256(const SecureString& sKey, const std::string& sCiphertext, const std::string& sIV, SecureString& sPlaintext)
  {
      // plaintext will always be equal to or lesser than length of ciphertext
      int nLen = sCiphertext.size();
      int nPLen = nLen, nFLen = 0;
  
      // Verify key sizes
      if (sKey.size() != 32 || sIV.size() != AES_BLOCK_SIZE) {
          LogPrintf("crypter DecryptAES256 - Invalid key or block size\n");
          return false;
      }
  
      sPlaintext.resize(nPLen);
  
      EVP_CIPHER_CTX ctx;
  
      bool fOk = true;
  
      EVP_CIPHER_CTX_init(&ctx);
      if (fOk) fOk = EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, (const unsigned char*)&sKey[0], (const unsigned char*)&sIV[0]);
      if (fOk) fOk = EVP_DecryptUpdate(&ctx, (unsigned char*)&sPlaintext[0], &nPLen, (const unsigned char*)&sCiphertext[0], nLen);
      if (fOk) fOk = EVP_DecryptFinal_ex(&ctx, (unsigned char*)(&sPlaintext[0]) + nPLen, &nFLen);
      EVP_CIPHER_CTX_cleanup(&ctx);
  
      if (!fOk) return false;
  
      sPlaintext.resize(nPLen + nFLen);
      return true;
  }
  
  
  bool CCryptoKeyStore::SetCrypted()
  {
      LOCK(cs_KeyStore);
      if (fUseCrypto)
          return true;
      if (!mapKeys.empty())
          return false;
      fUseCrypto = true;
      return true;
  }
  
  bool CCryptoKeyStore::Lock()
  {
      if (!SetCrypted())
          return false;
  
      {
          LOCK(cs_KeyStore);
          vMasterKey.clear();
      }
  
      NotifyStatusChanged(this);
      return true;
  }
  
  bool CCryptoKeyStore::Unlock(const CKeyingMaterial& vMasterKeyIn)
  {
      {
          LOCK(cs_KeyStore);
          if (!SetCrypted())
              return false;
  
          bool keyPass = false;
          bool keyFail = false;
          CryptedKeyMap::const_iterator mi = mapCryptedKeys.begin();
          for (; mi != mapCryptedKeys.end(); ++mi) {
              const CPubKey& vchPubKey = (*mi).second.first;
              const std::vector<unsigned char>& vchCryptedSecret = (*mi).second.second;
              CKeyingMaterial vchSecret;
              if (!DecryptSecret(vMasterKeyIn, vchCryptedSecret, vchPubKey.GetHash(), vchSecret)) {
                  keyFail = true;
                  break;
              }
              if (vchSecret.size() != 32) {
                  keyFail = true;
                  break;
              }
              CKey key;
              key.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());
              if (key.GetPubKey() != vchPubKey) {
                  keyFail = true;
                  break;
              }
              keyPass = true;
              if (fDecryptionThoroughlyChecked)
                  break;
          }
          if (keyPass && keyFail) {
              LogPrintf("The wallet is probably corrupted: Some keys decrypt but not all.");
              assert(false);
          }
          if (keyFail || !keyPass)
              return false;
          vMasterKey = vMasterKeyIn;
  
          if(!cryptedHDChain.IsNull()) {
              bool chainPass = false;
              // try to decrypt seed and make sure it matches
              CHDChain hdChainTmp;
              if (DecryptHDChain(hdChainTmp)) {
                  // make sure seed matches this chain
                  chainPass = cryptedHDChain.GetID() == hdChainTmp.GetSeedHash();
              }
              if (!chainPass) {
                  vMasterKey.clear();
                  return false;
              }
          }
          
          fDecryptionThoroughlyChecked = true;
      }
      NotifyStatusChanged(this);
      return true;
  }
  
  bool CCryptoKeyStore::AddKeyPubKey(const CKey& key, const CPubKey& pubkey)
  {
      {
          LOCK(cs_KeyStore);
          if (!IsCrypted())
              return CBasicKeyStore::AddKeyPubKey(key, pubkey);
  
          if (IsLocked())
              return false;
  
          std::vector<unsigned char> vchCryptedSecret;
          CKeyingMaterial vchSecret(key.begin(), key.end());
          if (!EncryptSecret(vMasterKey, vchSecret, pubkey.GetHash(), vchCryptedSecret))
              return false;
  
          if (!AddCryptedKey(pubkey, vchCryptedSecret))
              return false;
      }
      return true;
  }
  
  
  bool CCryptoKeyStore::AddCryptedKey(const CPubKey& vchPubKey, const std::vector<unsigned char>& vchCryptedSecret)
  {
      {
          LOCK(cs_KeyStore);
          if (!SetCrypted())
              return false;
  
          mapCryptedKeys[vchPubKey.GetID()] = make_pair(vchPubKey, vchCryptedSecret);
      }
      return true;
  }
  
  bool CCryptoKeyStore::GetKey(const CKeyID& address, CKey& keyOut) const
  {
      {
          LOCK(cs_KeyStore);
          if (!IsCrypted())
              return CBasicKeyStore::GetKey(address, keyOut);
  
          CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
          if (mi != mapCryptedKeys.end()) {
              const CPubKey& vchPubKey = (*mi).second.first;
              const std::vector<unsigned char>& vchCryptedSecret = (*mi).second.second;
              CKeyingMaterial vchSecret;
              if (!DecryptSecret(vMasterKey, vchCryptedSecret, vchPubKey.GetHash(), vchSecret))
                  return false;
              if (vchSecret.size() != 32)
                  return false;
              keyOut.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());
              return true;
          }
      }
      return false;
  }
  
  bool CCryptoKeyStore::GetPubKey(const CKeyID& address, CPubKey& vchPubKeyOut) const
  {
      {
          LOCK(cs_KeyStore);
          if (!IsCrypted())
              return CKeyStore::GetPubKey(address, vchPubKeyOut);
  
          CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
          if (mi != mapCryptedKeys.end()) {
              vchPubKeyOut = (*mi).second.first;
              return true;
          }
      }
      return false;
  }
  
  bool CCryptoKeyStore::EncryptKeys(CKeyingMaterial& vMasterKeyIn)
  {
      {
          LOCK(cs_KeyStore);
          if (!mapCryptedKeys.empty() || IsCrypted())
              return false;
  
          fUseCrypto = true;
          BOOST_FOREACH (KeyMap::value_type& mKey, mapKeys) {
              const CKey& key = mKey.second;
              CPubKey vchPubKey = key.GetPubKey();
              CKeyingMaterial vchSecret(key.begin(), key.end());
              std::vector<unsigned char> vchCryptedSecret;
              if (!EncryptSecret(vMasterKeyIn, vchSecret, vchPubKey.GetHash(), vchCryptedSecret))
                  return false;
              if (!AddCryptedKey(vchPubKey, vchCryptedSecret))
                  return false;
          }
          mapKeys.clear();
      }
      return true;
  }
  
  bool CCryptoKeyStore::EncryptHDChain(const CKeyingMaterial& vMasterKeyIn)
  {
      // should call EncryptKeys first
      if (!IsCrypted())
          return false;
  
      if (!cryptedHDChain.IsNull())
          return true;
  
      if (cryptedHDChain.IsCrypted())
          return true;
  
      // make sure seed matches this chain
      if (hdChain.GetID() != hdChain.GetSeedHash())
          return false;
  
      std::vector<unsigned char> vchCryptedSeed;
      if (!EncryptSecret(vMasterKeyIn, hdChain.GetSeed(), hdChain.GetID(), vchCryptedSeed))
          return false;
  
      // hdChain.Debug(__func__);
      cryptedHDChain = hdChain;
      cryptedHDChain.SetCrypted(true);
  
      SecureVector vchSecureCryptedSeed(vchCryptedSeed.begin(), vchCryptedSeed.end());
      if (!cryptedHDChain.SetSeed(vchSecureCryptedSeed, false))
          return false;
  
      SecureVector vchMnemonic;
      SecureVector vchMnemonicPassphrase;
  
      // it's ok to have no mnemonic if wallet was initialized via hdseed
      if (hdChain.GetMnemonic(vchMnemonic, vchMnemonicPassphrase)) {
          std::vector<unsigned char> vchCryptedMnemonic;
          std::vector<unsigned char> vchCryptedMnemonicPassphrase;
  
          if (!vchMnemonic.empty() && !EncryptSecret(vMasterKeyIn, vchMnemonic, hdChain.GetID(), vchCryptedMnemonic))
              return false;
          if (!vchMnemonicPassphrase.empty() && !EncryptSecret(vMasterKeyIn, vchMnemonicPassphrase, hdChain.GetID(), vchCryptedMnemonicPassphrase))
              return false;
  
          SecureVector vchSecureCryptedMnemonic(vchCryptedMnemonic.begin(), vchCryptedMnemonic.end());
          SecureVector vchSecureCryptedMnemonicPassphrase(vchCryptedMnemonicPassphrase.begin(), vchCryptedMnemonicPassphrase.end());
          if (!cryptedHDChain.SetMnemonic(vchSecureCryptedMnemonic, vchSecureCryptedMnemonicPassphrase, false))
              return false;
      }
  
      if (!hdChain.SetNull())
          return false;
  
      return true;
  }
  
  bool CCryptoKeyStore::DecryptHDChain(CHDChain& hdChainRet) const
  {
      if (!IsCrypted())
          return true;
      if (cryptedHDChain.IsNull())
          return false;
      if (!cryptedHDChain.IsCrypted())
          return false;
      SecureVector vchSecureSeed;
      SecureVector vchSecureCryptedSeed = cryptedHDChain.GetSeed();
      std::vector<unsigned char> vchCryptedSeed(vchSecureCryptedSeed.begin(), vchSecureCryptedSeed.end());
      if (!DecryptSecret(vMasterKey, vchCryptedSeed, cryptedHDChain.GetID(), vchSecureSeed))
          return false;
  
      hdChainRet = cryptedHDChain;
      if (!hdChainRet.SetSeed(vchSecureSeed, false))
          return false;
  
      // hash of decrypted seed must match chain id
      if (hdChainRet.GetSeedHash() != cryptedHDChain.GetID())
          return false;
  
      SecureVector vchSecureCryptedMnemonic;
      SecureVector vchSecureCryptedMnemonicPassphrase;
  
      // it's ok to have no mnemonic if wallet was initialized via hdseed
      if (cryptedHDChain.GetMnemonic(vchSecureCryptedMnemonic, vchSecureCryptedMnemonicPassphrase)) {
          SecureVector vchSecureMnemonic;
          SecureVector vchSecureMnemonicPassphrase;
  
          std::vector<unsigned char> vchCryptedMnemonic(vchSecureCryptedMnemonic.begin(), vchSecureCryptedMnemonic.end());
          std::vector<unsigned char> vchCryptedMnemonicPassphrase(vchSecureCryptedMnemonicPassphrase.begin(), vchSecureCryptedMnemonicPassphrase.end());
  
          if (!vchCryptedMnemonic.empty() && !DecryptSecret(vMasterKey, vchCryptedMnemonic, cryptedHDChain.GetID(), vchSecureMnemonic))
              return false;
          if (!vchCryptedMnemonicPassphrase.empty() && !DecryptSecret(vMasterKey, vchCryptedMnemonicPassphrase, cryptedHDChain.GetID(), vchSecureMnemonicPassphrase))
              return false;
          if (!hdChainRet.SetMnemonic(vchSecureMnemonic, vchSecureMnemonicPassphrase, false))
              return false;
      }
  
      hdChainRet.SetCrypted(false);
      // hdChainRet.Debug(__func__);
  
      return true;
  }
  
  bool CCryptoKeyStore::SetHDChain(const CHDChain& chain)
  {
      if (IsCrypted())
          return false;
  
      if (chain.IsCrypted())
          return false;
  
      hdChain = chain;
      return true;
  }
  
  bool CCryptoKeyStore::SetCryptedHDChain(const CHDChain& chain)
  {
      if (!SetCrypted())
          return false;
  
      if (!chain.IsCrypted())
          return false;
  
      cryptedHDChain = chain;
      return true;
  }
  
  bool CCryptoKeyStore::GetHDChain(CHDChain& hdChainRet) const
  {
      if(IsCrypted()) {
          hdChainRet = cryptedHDChain;
          return !cryptedHDChain.IsNull();
      }
  
      hdChainRet = hdChain;
      return !hdChain.IsNull();
  }