(Java) Streaming Encryption

Encrypt and decrypt using a stream.

Chilkat Java Downloads Java Libs for Windows, MacOS, Linux, Alpine Linux, Solaris Java Libs for Android

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkCrypt2 crypt = new CkCrypt2();

    // Setup encryption using the chacha20 algorithm...
    crypt.put_CryptAlgorithm("chacha20");
    crypt.put_KeyLength(256);
    crypt.put_EncodingMode("hex");
    String ivHex = "000000000000000000000002";
    crypt.SetEncodedIV(ivHex,"hex");
    crypt.put_InitialCount(42);
    String keyHex = "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0";
    crypt.SetEncodedKey(keyHex,"hex");

    String plainText = "The quick brown fox jumped over the lazy dog.\r\n";

    CkStream stream = new CkStream();

    // We'll save the encrypted output in eStrings to demonstrate streaming decryption next.
    CkStringArray eStrings = new CkStringArray();

    // Start a background task that will encrypt a stream.
    CkTask task = crypt.EncryptStreamAsync(stream);
    boolean success = task.Run();

    // Write plainText to the stream, and read chacha20 encrypted text..
    String cipherText;
    int i;
    for (i = 1; i <= 10; i++) {
        // Note: An encryption algorithm's block size will cause buffering,
        // and therefore not every loop iteration will produce output.
        success = stream.WriteString(plainText);
        if (stream.get_DataAvailable() == true) {
            cipherText = stream.readBytesENC("hex");
            System.out.println(cipherText);
            success = eStrings.Append(cipherText);
            }

        }

    // Tell the background task that the stream has ended.
    success = stream.WriteClose();

    // Let's make sure the background task finished.
    // It should already be the case that the task is finished.
    while ((task.get_Finished() != true)) {
        task.SleepMs(20);
        }

    // Get any remaining data available from the stream.
    if (stream.get_DataAvailable() == true) {
        cipherText = stream.readBytesENC("hex");
        System.out.println(cipherText);
        success = eStrings.Append(cipherText);
        }

    if (task.get_TaskSuccess() != true) {
        System.out.println("async encryption failed:");
        System.out.println(task.resultErrorText());
        success = false;
        }

    System.out.println("-- encrypt finished --");

    // Now decrypt to return the original.

    // Reset the stream object so it can be used again.
    stream.Reset();

    // Start a background task that will decrypt a stream.
    task = crypt.DecryptStreamAsync(stream);
    success = task.Run();

    int n = eStrings.get_Count();
    for (i = 0; i <= n - 1; i++) {
        success = stream.WriteBytesENC(eStrings.getString(i),"hex");
        if (stream.get_DataAvailable() == true) {
            plainText = stream.readString();
            System.out.println(plainText);
            }

        }

    // Tell the background task that the stream has ended.
    success = stream.WriteClose();

    // Let's make sure the background task finished.
    // It should already be the case that the task is finished.
    while ((task.get_Finished() != true)) {
        task.SleepMs(20);
        }

    // Get any remaining data available from the stream.
    if (stream.get_DataAvailable() == true) {
        plainText = stream.readString();
        System.out.println(plainText);
        }

    if (task.get_TaskSuccess() != true) {
        System.out.println("async decryption failed:");
        System.out.println(task.resultErrorText());
        success = false;
        }

    System.out.println("-- decrypt finished --");
  }
}