MultiBit HD / Technical library

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mbhd-core/src/main/java/org/multibit/hd/core/crypto/EncryptedFileReaderWriter.java

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1package org.multibit.hd.core.crypto;23import com.google.common.base.Charsets;4import com.google.common.base.Preconditions;5import com.google.common.collect.Lists;6import com.google.common.io.ByteStreams;7import com.google.common.io.Files;8import com.google.protobuf.ByteString;9import org.bitcoinj.crypto.KeyCrypterScrypt;10import org.bitcoinj.wallet.Protos;11import org.multibit.commons.crypto.AESUtils;12import org.multibit.hd.core.dto.WalletSummary;13import org.multibit.hd.core.exceptions.EncryptedFileReaderWriterException;14import org.multibit.commons.files.SecureFiles;15import org.multibit.hd.core.files.EncryptedFileListItem;16import org.multibit.hd.core.managers.WalletManager;17import org.slf4j.Logger;18import org.slf4j.LoggerFactory;19import org.spongycastle.crypto.params.KeyParameter;2021import java.io.*;22import java.security.SecureRandom;23import java.util.Arrays;24import java.util.List;2526/**27 * <p>Reader / Writer to provide the following to Services:<br>28 * <ul>29 * <li>load an AES encrypted file</li>30 * <li>write an AES encrypted file</li>31 * </ul>32 * Example:<br>33 * <pre>34 * </pre>35 * </p>36 */37public class EncryptedFileReaderWriter {38  private static final Logger log = LoggerFactory.getLogger(EncryptedFileReaderWriter.class);3940  private static final String TEMPORARY_FILE_EXTENSION = ".tmp";41  private static final String OLD_FILE_EXTENSION = ".old";42  private static final String NEW_FILE_EXTENSION = ".new";4344  /**45   * Decrypt an AES encrypted file and return it as an inputStream46   */47  public static ByteArrayInputStream readAndDecrypt(EncryptedFileListItem encryptedProtobufFile, CharSequence password) throws EncryptedFileReaderWriterException {48    return new ByteArrayInputStream(readAndDecryptToByteArray(encryptedProtobufFile, password));49  }5051  /**52   * Decrypt an AES encrypted file and return it as a byte array53   */54  public static byte[] readAndDecryptToByteArray(EncryptedFileListItem encryptedProtobufFile, CharSequence password) throws EncryptedFileReaderWriterException {55      Preconditions.checkNotNull(encryptedProtobufFile);56      Preconditions.checkNotNull(password);57      try {58          // Read the encrypted file in and decrypt it.59          log.debug("Encrypted file is of size {} bytes", encryptedProtobufFile.length());60          byte[] fileBytes = Files.toByteArray(encryptedProtobufFile);61          byte[] ivBytes = Arrays.copyOfRange(fileBytes, 0, 16);62          byte[] encryptedWalletBytes = Arrays.copyOfRange(fileBytes, 16, fileBytes.length);6364          KeyCrypterScrypt keyCrypterScrypt = new KeyCrypterScrypt(makeScryptParameters(WalletManager.scryptSalt()));65          KeyParameter keyParameter = keyCrypterScrypt.deriveKey(password);66          byte [] decryptedBytes = AESUtils.decrypt(encryptedWalletBytes,keyParameter,ivBytes);67          InputStream inputStream = new ByteArrayInputStream(decryptedBytes);68          if(!encryptedProtobufFile.isValidDecryption(inputStream)){69              decryptedBytes = AESUtils.decrypt(fileBytes,keyParameter,WalletManager.deprecatedFixedAesInitializationVector());70          }71          // Decrypt the file bytes72          return decryptedBytes;73      } catch (Exception e) {7475          throw new EncryptedFileReaderWriterException("Cannot read and decrypt the file '" + encryptedProtobufFile.getAbsolutePath() + "'", e);76      }77  }7879  /**80   * Encrypt a byte array and output to a file, using an intermediate temporary file81   */82  public static void encryptAndWrite(byte[] unencryptedBytes, CharSequence password, File outputFile) throws EncryptedFileReaderWriterException {83    try {84      byte[] encryptedBytes = encrypt(unencryptedBytes, password);8586      ByteArrayInputStream encryptedWalletByteArrayInputStream = new ByteArrayInputStream(encryptedBytes);87      File temporaryFile = new File(outputFile.getAbsolutePath() + TEMPORARY_FILE_EXTENSION);88      SecureFiles.writeFile(encryptedWalletByteArrayInputStream, temporaryFile, outputFile);89    } catch (Exception e) {90      throw new EncryptedFileReaderWriterException("Cannot encryptAndWrite", e);91    }92  }9394  /**95   * Encrypt a byte array and output directly to a file96   */97  public static void encryptAndWriteDirect(byte[] unencryptedBytes, CharSequence password, File outputFile) throws EncryptedFileReaderWriterException {98    try {99      byte[] encryptedBytes = encrypt(unencryptedBytes, password);100101      ByteArrayInputStream encryptedWalletByteArrayInputStream = new ByteArrayInputStream(encryptedBytes);102      SecureFiles.writeFile(encryptedWalletByteArrayInputStream, outputFile);103    } catch (Exception e) {104      throw new EncryptedFileReaderWriterException("Cannot encryptAndWriteDirect", e);105    }106  }107  /**108   * Encrypt the file specified using the backup AES key derived from the supplied credentials109   *110   * @param fileToEncrypt file to encrypt111   * @param password      credentials to use to do the encryption112   * @return the resultant encrypted file113   * @throws EncryptedFileReaderWriterException114   */115  public static File makeBackupAESEncryptedCopyAndDeleteOriginal(File fileToEncrypt, String password, WalletSummary walletSummary) throws EncryptedFileReaderWriterException {116    Preconditions.checkNotNull(fileToEncrypt);117    Preconditions.checkNotNull(password);118    Preconditions.checkNotNull(walletSummary.getEncryptedBackupKey());119    Preconditions.checkNotNull(walletSummary.getInitializationVector());120    try {121      // Decrypt the backup AES key stored in the wallet summary122      KeyParameter walletPasswordDerivedAESKey = AESUtils.createAESKey(password.getBytes(Charsets.UTF_8), WalletManager.scryptSalt());123      byte[] backupAESKeyBytes = AESUtils.decrypt(walletSummary.getEncryptedBackupKey(), walletPasswordDerivedAESKey,walletSummary.getInitializationVector());124      KeyParameter backupAESKey = new KeyParameter(backupAESKeyBytes);125      File destinationFile = new File(fileToEncrypt.getAbsoluteFile() + WalletManager.MBHD_AES_SUFFIX);126127      return encryptAndDeleteOriginal(fileToEncrypt, destinationFile, backupAESKey);128    } catch (Exception e) {129      throw new EncryptedFileReaderWriterException("Could not decrypt backup AES key", e);130    }131  }132133  /**134   * Encrypt the file specified using an AES key derived from the supplied credentials135   *136   * @param fileToEncrypt file to encrypt137   * @param password      credentials to use to do the encryption138   * @return the resultant encrypted file139   * @throws EncryptedFileReaderWriterException140   */141  public static File makeAESEncryptedCopyAndDeleteOriginal(File fileToEncrypt, CharSequence password) throws EncryptedFileReaderWriterException {142    Preconditions.checkNotNull(fileToEncrypt);143    Preconditions.checkNotNull(password);144145    File destinationFile = new File(fileToEncrypt.getAbsoluteFile() + WalletManager.MBHD_AES_SUFFIX);146    return makeAESEncryptedCopyAndDeleteOriginal(fileToEncrypt, destinationFile, password);147  }148149  /**150   * Encrypt the file specified using an AES key derived from the supplied credentials151   *152   * @param fileToEncrypt   file to encrypt153   * @param destinationFile destination file (if not set then fileToEncrypt + .aes154   * @param password        credentials to use to do the encryption155   * @return the resultant encrypted file156   * @throws EncryptedFileReaderWriterException157   */158  public static File makeAESEncryptedCopyAndDeleteOriginal(File fileToEncrypt, File destinationFile, CharSequence password) throws EncryptedFileReaderWriterException {159    Preconditions.checkNotNull(fileToEncrypt);160    Preconditions.checkNotNull(destinationFile);161    Preconditions.checkNotNull(password);162163    KeyCrypterScrypt keyCrypterScrypt = new KeyCrypterScrypt(makeScryptParameters(WalletManager.scryptSalt()));164    KeyParameter keyParameter = keyCrypterScrypt.deriveKey(password);165    return encryptAndDeleteOriginal(fileToEncrypt, destinationFile, keyParameter);166  }167168  /**169   * Change the encryption on Collection of files.170   * This method is split into two parts:171   * 1) changeEncryptionPrepare - change the encryption on the files, giving them the suffix ".new"172   * 2) changeEncryptionCommit - rename the files173   *174   * @param files       The List of files to change the encryption on175   * @param oldPassword The original password176   * @param newPassword The new password177   * @return newFiles   A list containing the newly encrypted files178   * @throws EncryptedFileReaderWriterException179   */180  public static List<EncryptedFileListItem> changeEncryptionPrepare(List<EncryptedFileListItem> files, CharSequence oldPassword, CharSequence newPassword) throws IOException {181      Preconditions.checkNotNull(files);182      Preconditions.checkNotNull(oldPassword);183      Preconditions.checkNotNull(newPassword);184185      // The files are expected to end with ".aes"186      for (EncryptedFileListItem fileToCheck : files) {187          Preconditions.checkState(fileToCheck.getAbsolutePath().endsWith(WalletManager.MBHD_AES_SUFFIX));188      }189190      List<EncryptedFileListItem> newFiles = Lists.newArrayList();191      KeyCrypterScrypt keyCrypterScrypt = new KeyCrypterScrypt(makeScryptParameters(WalletManager.scryptSalt()));192      KeyParameter oldKeyParameter = keyCrypterScrypt.deriveKey(oldPassword);193      KeyParameter newKeyParameter = keyCrypterScrypt.deriveKey(newPassword);194195      for (EncryptedFileListItem file : files) {196          log.debug("Processing file\n'{}'", file.getAbsolutePath());197          EncryptedFileListItem newFile = new EncryptedFileListItem(file.getAbsolutePath() + NEW_FILE_EXTENSION) {198              @Override199              public boolean isValidDecryption(InputStream inputStream) throws IOException {200                  return false;201              }202          };203          newFiles.add(newFile);204          if (file.exists()) {205              // Read in the file bytes that are encrypted with the old password206              byte[] oldFileBytes = Files.toByteArray(file);207              byte[] ivBytes = Arrays.copyOfRange(oldFileBytes, 0, 16);208              byte[] encryptedWalletBytes = Arrays.copyOfRange(oldFileBytes, 16, oldFileBytes.length);209              byte[] plainBytes = AESUtils.decrypt(encryptedWalletBytes, oldKeyParameter, ivBytes);210              InputStream byteArrayInputStream= new ByteArrayInputStream(plainBytes);211              if(!file.isValidDecryption(byteArrayInputStream)){212                  plainBytes = AESUtils.decrypt(oldFileBytes,oldKeyParameter,WalletManager.deprecatedFixedAesInitializationVector());213              }214              byte[] newEncryptedBytes = encrypt(plainBytes, newKeyParameter);215              // Write out the bytes to a file with the suffix ".new"216              SecureFiles.writeFile(new ByteArrayInputStream(newEncryptedBytes), newFile);217          }218      }219      return newFiles;220  }221222223  /**224   * Change the encryption on Collection of files.225   * This method is split into two parts:226   * 1) changeEncryptionPrepare - change the encryption on the files, giving them the suffix ".new"227   * 2) changeEncryptionCommit - rename the files to  ".old", rename the ".new" files to the original, secure delete the ".old"228   *229   * @param originalFiles The List of files to change the encryption on230   * @param newFiles      The list of new files, after their encryption has been changed231   * @throws EncryptedFileReaderWriterException232   */233  public static void changeEncryptionCommit(List<EncryptedFileListItem> originalFiles, List<EncryptedFileListItem> newFiles) throws EncryptedFileReaderWriterException {234    Preconditions.checkNotNull(originalFiles);235    Preconditions.checkNotNull(newFiles);236    Preconditions.checkState(originalFiles.size() == newFiles.size());237238    // Once all files have been written to the ".new" files, rename the files to have the suffix ".old"239    List<File> oldFiles = Lists.newArrayList();240    for (int index = 0; index < originalFiles.size(); index++) {241       try {242        // Rename the file, giving it the suffix ".old"243        File oldFile = new File(originalFiles.get(index).getAbsolutePath() + OLD_FILE_EXTENSION);244        oldFiles.add(oldFile);245         if (originalFiles.get(index).exists()){246           SecureFiles.rename(originalFiles.get(index), oldFile);247           log.debug("Renamed:\n'{}'\n'{}'", originalFiles.get(index).getAbsolutePath(), oldFile.getAbsolutePath());248         }249       } catch (IOException ioe) {250         throw new EncryptedFileReaderWriterException("Could not rename file " + originalFiles.get(index).getAbsolutePath() + " to " + oldFiles.get(index).getAbsolutePath());251       }252     }253254    // Rename all the new files to the original ones passed in255    for (int index = 0; index < originalFiles.size(); index++) {256      try {257        if (newFiles.get(index).exists()) {258          SecureFiles.rename(newFiles.get(index), originalFiles.get(index));259          log.debug("Renamed:\n'{}'\n'{}'", newFiles.get(index).getAbsolutePath(), originalFiles.get(index).getAbsolutePath());260        }261      } catch (IOException ioe) {262        throw new EncryptedFileReaderWriterException("Could not rename file " + newFiles.get(index).getAbsolutePath() + " to " + originalFiles.get(index).getAbsolutePath());263      }264    }265266    // Secure delete the old files267    for (File fileToDelete : oldFiles) {268      try {269        if (fileToDelete.exists()) {270          SecureFiles.secureDelete(fileToDelete);271        }272      } catch (IOException ioe) {273        throw new EncryptedFileReaderWriterException("Could not delete file " + fileToDelete);274      }275    }276  }277278  public static Protos.ScryptParameters makeScryptParameters(byte[] salt) {279    Protos.ScryptParameters.Builder scryptParametersBuilder = Protos.ScryptParameters.newBuilder().setSalt(ByteString.copyFrom(salt));280    return scryptParametersBuilder.build();281  }282283284  /**285   * Encrypt a file and delete the original286   * @param fileToEncrypt the file to encrypt287   * @param encryptedFilename the encrypted filename288   * @param keyParameter the KeyParameter used to encrypt the file289   * @return the encrypted file - will be null if no encryption was done290   * @throws EncryptedFileReaderWriterException291   */292  private static synchronized File encryptAndDeleteOriginal(File fileToEncrypt, File encryptedFilename, KeyParameter keyParameter) throws EncryptedFileReaderWriterException {293    Preconditions.checkNotNull(encryptedFilename);294    Preconditions.checkNotNull(keyParameter);295    if (fileToEncrypt == null || !fileToEncrypt.exists()) {296      log.debug("Not encrypting file {} as it does not exist", fileToEncrypt == null ? "null" : fileToEncrypt.getAbsolutePath());297      // Nothing to do298      return null;299    }300301    FileOutputStream encryptedWalletOutputStream = null;302    try {303      // Read in the file304      byte[] unencryptedBytes = Files.toByteArray(fileToEncrypt);305      byte[] encryptedBytes = encrypt(unencryptedBytes, keyParameter);306307      // Save encrypted bytes308      ByteArrayInputStream encryptedWalletByteArrayInputStream = new ByteArrayInputStream(encryptedBytes);309      encryptedWalletOutputStream = new FileOutputStream(encryptedFilename);310      ByteStreams.copy(encryptedWalletByteArrayInputStream, encryptedWalletOutputStream);311      encryptedWalletOutputStream.flush();312313      if (encryptedFilename.length() == encryptedBytes.length) {314        SecureFiles.secureDelete(fileToEncrypt);315      } else {316        // The saved file isn't the correct size - do not delete the original317        throw new EncryptedFileReaderWriterException("The saved file " + encryptedFilename + " is not the size of the encrypted bytes - not deleting the original file");318      }319320      return encryptedFilename;321322    } catch (Exception e) {323      throw new EncryptedFileReaderWriterException("Cannot make encrypted copy for file '" + fileToEncrypt.getAbsolutePath() + "'", e);324    } finally {325      if (encryptedWalletOutputStream != null) {326        try {327          encryptedWalletOutputStream.close();328          encryptedWalletOutputStream = null;329        } catch (IOException e) {330          log.error("Cannot close wallet output stream", e);331        }332      }333    }334  }335336  /**337   * Encrypt a byte array, returning the encrypted byte array.338   * this method checks the encryption is reversible339   *340   * @param unencryptedBytes the unencrypted bytes you want to encrypt341   * @param keyParameter     the KeyParameter to use342   * @return encryptedBytes the encryptedBytes343   */344  private static byte[] encrypt(byte[] unencryptedBytes, KeyParameter keyParameter) {345    try {346      // Create an AES encoded version of the unencryptedBytes, using the credentials347      byte[] randomIvBytes = WalletManager.generateRandomIv();348      byte[] encryptedBytes = AESUtils.encrypt(unencryptedBytes,keyParameter,randomIvBytes);349      byte[] rebornBytes = AESUtils.decrypt(encryptedBytes,keyParameter,randomIvBytes);350      byte[] fileBytes = appendByteArrays(randomIvBytes,encryptedBytes);351      if (Arrays.equals(unencryptedBytes, rebornBytes)) {352        return fileBytes;353      } else {354        throw new EncryptedFileReaderWriterException("The encryption was not reversible so aborting.");355      }356    } catch (Exception e) {357      throw new EncryptedFileReaderWriterException("Cannot encryptAndWrite", e);358    }359  }360361  /**362   * Encrypt a byte array, returning the encrypted byte array.363   * this method checks the encryption is reversible364   *365   * @param unencryptedBytes the unencrypted bytes you want to encrypt366   * @param password         the password to use367   * @return encryptedBytes the encryptedBytes368   */369  private static byte[] encrypt(byte[] unencryptedBytes, CharSequence password) {370    try {371      KeyCrypterScrypt keyCrypterScrypt = new KeyCrypterScrypt(makeScryptParameters(WalletManager.scryptSalt()));372      KeyParameter keyParameter = keyCrypterScrypt.deriveKey(password);373374      return encrypt(unencryptedBytes, keyParameter);375    } catch (Exception e) {376      throw new EncryptedFileReaderWriterException("Cannot encryptAndWrite", e);377    }378  }379380  private static byte[] appendByteArrays(byte [] firstByteArray,byte [] secondByteArray){381    byte [] resultByteArray = new byte[firstByteArray.length+secondByteArray.length];382    System.arraycopy(firstByteArray, 0, resultByteArray, 0, firstByteArray.length);383    // copy encrypted bytes into end of destination (from pos iv.length,encryptedBytes.length)384    System.arraycopy(secondByteArray, 0, resultByteArray, firstByteArray.length, secondByteArray.length);385    return resultByteArray;386  }387}