com.github.isaichkindanila.crypt.lib.file.FileEncryptor Maven / Gradle / Ivy

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Simple Java library for stream ciphers based encryption
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package com.github.isaichkindanila.crypt.lib.file;

import com.github.isaichkindanila.crypt.lib.cipher.StandardStreamCipher;
import com.github.isaichkindanila.crypt.lib.stream.EncryptedOutputStream;
import com.github.isaichkindanila.crypt.lib.util.IOUtils;

import java.io.*;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;

/**
 * Class used to encrypt files.
 *
 * @see FileDecryptor
 */
@SuppressWarnings("WeakerAccess")
public class FileEncryptor {
    /**
     * Extension of encrypted files.
     */
    public static final String FILE_EXTENSION = "crypt";

    private final IOHandler ioHandler;
    private final OutputStream out;
    private final List fileWrappers;
    private long total;

    /**
     * @param file       file or directory that will be encrypted
     * @param targetDir  directory where encrypted file will be put
     * @param targetName name (without extension) of encrypted file
     * @param cipher     stream cipher to be used to encrypt files
     * @param password   password to be used to encrypt files
     * @throws IOException              if IOException occurs while writing stream header
     * @throws IllegalArgumentException if file to be encrypted does not exist
     */
    public FileEncryptor(File file,
                         File targetDir,
                         String targetName,
                         StandardStreamCipher cipher,
                         String password) throws IOException {
        if (!file.exists()) {
            throw new IllegalArgumentException("file does not exist");
        }

        if (!targetDir.exists() && !targetDir.mkdirs()) {
            throw new FileNotFoundException("directory '" + targetDir.getAbsolutePath() + "' does not exist and cannot be created");
        }

        File target = new File(targetDir, targetName + "." + FILE_EXTENSION);
        OutputStream fileOut = new FileOutputStream(target);
        OutputStream buffered = new BufferedOutputStream(fileOut);

        out = new EncryptedOutputStream(buffered, cipher, password);
        ioHandler = new IOHandler();

        fileWrappers = new ArrayList<>();
        total = createWrappers(file, "");
    }

    /**
     * Uses {@link StandardStreamCipher#ChaCha8 ChaCha8} stream cipher to encrypt files.
     *
     * @param file       file or directory that will be encrypted
     * @param targetDir  directory where encrypted file will be put
     * @param targetName name (without extension) of encrypted file
     * @param password   password to be used to encrypt files
     * @throws IOException if IOException occurs while writing stream header
     */
    public FileEncryptor(File file, File targetDir, String targetName, String password) throws IOException {
        this(file, targetDir, targetName, StandardStreamCipher.ChaCha8, password);
    }

    /**
     * Encrypted file name will be concatenation of original file name, a dot and {@link #FILE_EXTENSION}.
     *
     * @param file      file or directory that will be encrypted
     * @param targetDir directory where encrypted file will be put
     * @param cipher    stream cipher to be used to encrypt files
     * @param password  password to be used to encrypt files
     * @throws IOException if IOException occurs while writing stream header
     */
    public FileEncryptor(File file, File targetDir, StandardStreamCipher cipher, String password) throws IOException {
        this(file, targetDir, file.getName(), cipher, password);
    }

    /**
     * Uses {@link StandardStreamCipher#ChaCha8 ChaCha8} stream cipher to encrypt files.
     * 
     * Encrypted file name will be concatenation of original file name, a dot and {@link #FILE_EXTENSION}.
     *
     * @param file      file or directory that will be encrypted
     * @param targetDir directory where encrypted file will be put
     * @param password  password to be used to encrypt files
     * @throws IOException if IOException occurs while writing stream header
     */
    public FileEncryptor(File file, File targetDir, String password) throws IOException {
        this(file, targetDir, file.getName(), password);
    }

    private long createWrappers(File file, String path) {
        if (file.isDirectory()) {
            File[] children = file.listFiles();
            long size = 0;

            if (children != null) {
                path += file.getName() + "/";

                for (File f : children) {
                    size += createWrappers(f, path);
                }
            }

            return size;
        } else {
            fileWrappers.add(new FileWrapper(file, path + file.getName()));
            return file.length();
        }
    }

    private void encrypt(FileWrapper wrapper) throws IOException {
        IOUtils.writeByteArray(wrapper.path.getBytes(StandardCharsets.UTF_8), out);
        IOUtils.writeLong(wrapper.file.length(), out);

        ioHandler.copy(wrapper.file, out);
    }

    /**
     * Encrypts file or directory passed in constructor.
     *
     * @throws IOException if IOException occurs
     */
    public void encrypt() throws IOException {
        IOUtils.writeLong(total, out);
        IOUtils.writeInt(fileWrappers.size(), out);

        for (FileWrapper wrapper : fileWrappers) {
            encrypt(wrapper);
        }

        out.close();
    }

    /**
     * Returns value in range [0, 1] representing encryption progress,
     * where 0 means "not started yet" and 1 means "already finished".
     *
     * @return double value in range [0, 1]
     */
    public double progress() {
        return total == 0 ? 1.0 : 1.0 * ioHandler.done / total;
    }

    private static class FileWrapper {
        private final File file;
        private final String path;

        private FileWrapper(File file, String path) {
            this.file = file;
            this.path = path;
        }
    }
}