/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.crypto.examples;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.charset.StandardCharsets;
  import java.util.Arrays;
  import java.util.Properties;
  
  import javax.crypto.spec.IvParameterSpec;
  import javax.crypto.spec.SecretKeySpec;
  
  import org.apache.commons.crypto.stream.CryptoInputStream;
  import org.apache.commons.crypto.stream.CryptoOutputStream;
  import org.apache.commons.crypto.utils.AES;
  
  /**
   * Example showing how to use stream encryption and decryption.
   */
  public class StreamExample {
  
      /**
       * Converts String to UTF8 bytes
       *
       * @param input the input string
       * @return UTF8 bytes
       */
      private static byte[] getUTF8Bytes(final String input) {
          return input.getBytes(StandardCharsets.UTF_8);
      }
  
      public static void main(final String []args) throws IOException {
          final SecretKeySpec key = AES.newSecretKeySpec(getUTF8Bytes("1234567890123456"));
          final IvParameterSpec iv = new IvParameterSpec(getUTF8Bytes("1234567890123456"));
          final Properties properties = new Properties();
          final String transform = AES.CBC_PKCS5_PADDING;
  
          final String input = "hello world!";
          //Encryption with CryptoOutputStream.
  
          final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
  
          try (CryptoOutputStream cos = new CryptoOutputStream(transform, properties, outputStream, key, iv)) {
              cos.write(getUTF8Bytes(input));
              cos.flush();
          }
  
          // The encrypted data:
          System.out.println("Encrypted: "+Arrays.toString(outputStream.toByteArray()));
  
          // Decryption with CryptoInputStream.
          final InputStream inputStream = new ByteArrayInputStream(outputStream.toByteArray());
  
          try (CryptoInputStream cis = new CryptoInputStream(transform, properties, inputStream, key, iv)) {
              final byte[] decryptedData = new byte[1024];
              int decryptedLen = 0;
              int i;
              while ((i = cis.read(decryptedData, decryptedLen, decryptedData.length - decryptedLen)) > -1) {
                  decryptedLen += i;
              }
              System.out.println("Decrypted: "+new String(decryptedData, 0, decryptedLen, StandardCharsets.UTF_8));
          }
      }
  
  }