详解Android使用Socket对大文件进行加密传输

 //秘钥算法
 private static final String KEY_ALGORITHM = "DES";
 //加密算法：algorithm/mode/padding 算法/工作模式/填充模式
 private static final String CIPHER_ALGORITHM = "DES/ECB/PKCS5Padding";
 //秘钥
 private static final String KEY = "12345678";//DES秘钥长度必须是8位

 public static void main(String args[]) {
  String data = "加密解密";
  KLog.d("加密数据：" + data);
  byte[] encryptData = encrypt(data.getBytes());
  KLog.d("加密后的数据：" + new String(encryptData));
  byte[] decryptData = decrypt(encryptData);
  KLog.d("解密后的数据：" + new String(decryptData));
 }

 public static byte[] encrypt(byte[] data) {
  //初始化秘钥
  SecretKey secretKey = new SecretKeySpec(KEY.getBytes(), KEY_ALGORITHM);

  try {
   Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
   cipher.init(Cipher.ENCRYPT_MODE, secretKey);
   byte[] result = cipher.doFinal(data);
   return Base64.getEncoder().encode(result);
  } catch (Exception e) {
   e.printStackTrace();
  }
  return null;
 }

 public static byte[] decrypt(byte[] data) {
  byte[] resultBase64 = Base64.getDecoder().decode(data);
  SecretKey secretKey = new SecretKeySpec(KEY.getBytes(), KEY_ALGORITHM);

  try {
   Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
   cipher.init(Cipher.DECRYPT_MODE, secretKey);
   byte[] result = cipher.doFinal(resultBase64);
   return result;
  } catch (Exception e) {
   e.printStackTrace();
  }
  return null;
 }

 Socket socket = new Socket(ApiConstants.HOST, ApiConstants.PORT);
 OutputStream outStream = socket.getOutputStream();

 InputStream inStream = socket.getInputStream();
 RandomAccessFile fileOutStream = new RandomAccessFile(file, "r");
 fileOutStream.seek(0);
 byte[] buffer = new byte[1024];
 int len = -1;
 while (((len = fileOutStream.read(buffer)) != -1)) {
  outStream.write(buffer, 0, len); // 这里进行字节流的传输
 }

 fileOutStream.close();
 outStream.close();
 inStream.close();
 socket.close();

 Socket socket = server.accept();
 InputStream inStream = socket.getInputStream();
 OutputStream outStream = socket.getOutputStream();
 outStream.write(response.getBytes("UTF-8"));
 RandomAccessFile fileOutStream = new RandomAccessFile(file, "rwd");
 fileOutStream.seek(0);
 byte[] buffer = new byte[1024];
 int len;
 while ((len = inStream.read(buffer)) != -1) { // 从字节输入流中读取数据写入到文件中
  fileOutStream.write(buffer, 0, len);
 }

 fileOutStream.close();
 inStream.close();
 outStream.close();
 socket.close();

 while (((len = fileOutStream.read(buffer)) != -1)) {
  outStream.write(DesUtil.encrypt(buffer) ,0, len); // 对字节数组进行加密
 }

 while ((len = inStream.read(buffer)) != -1) {
  fileOutStream.write(DesUtil.decrypt(buffer), 0, len); // 对字节数组进行解密
 }

public class FileDesUtil {
 //秘钥算法
 private static final String KEY_ALGORITHM = "DES";
 //加密算法：algorithm/mode/padding 算法/工作模式/填充模式
 private static final String CIPHER_ALGORITHM = "DES/ECB/PKCS5Padding";
 private static final byte[] KEY = {56, 57, 58, 59, 60, 61, 62, 63};//DES 秘钥长度必须是8 位或以上

 /**
  * 文件进行加密并保存加密后的文件到指定目录
  *
  * @param fromFile 要加密的文件 如c:/test/待加密文件.txt
  * @param toFile 加密后存放的文件 如c:/加密后文件.txt
  */
 public static void encrypt(String fromFilePath, String toFilePath) {
  KLog.i("encrypting...");

  File fromFile = new File(fromFilePath);
  if (!fromFile.exists()) {
   KLog.e("to be encrypt file no exist!");
   return;
  }
  File toFile = getFile(toFilePath);

  SecretKey secretKey = new SecretKeySpec(KEY, KEY_ALGORITHM);
  InputStream is = null;
  OutputStream out = null;
  CipherInputStream cis = null;
  try {
   Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
   cipher.init(Cipher.ENCRYPT_MODE, secretKey);
   is = new FileInputStream(fromFile);
   out = new FileOutputStream(toFile);
   cis = new CipherInputStream(is, cipher);
   byte[] buffer = new byte[1024];
   int r;
   while ((r = cis.read(buffer)) > 0) {
    out.write(buffer, 0, r);
   }
  } catch (Exception e) {
   KLog.e(e.toString());
  } finally {
   try {
    if (cis != null) {
     cis.close();
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
   try {
    if (is != null) {
     is.close();
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
   try {
    if (out != null) {
     out.close();
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
  }

  KLog.i("encrypt completed");
 }

 @NonNull
 private static File getFile(String filePath) {
  File fromFile = new File(filePath);
  if (!fromFile.getParentFile().exists()) {
   fromFile.getParentFile().mkdirs();
  }
  return fromFile;
 }

 /**
  * 文件进行解密并保存解密后的文件到指定目录
  *
  * @param fromFilePath 已加密的文件 如c:/加密后文件.txt
  * @param toFilePath 解密后存放的文件 如c:/ test/解密后文件.txt
  */
 public static void decrypt(String fromFilePath, String toFilePath) {
  KLog.i("decrypting...");

  File fromFile = new File(fromFilePath);
  if (!fromFile.exists()) {
   KLog.e("to be decrypt file no exist!");
   return;
  }
  File toFile = getFile(toFilePath);

  SecretKey secretKey = new SecretKeySpec(KEY, KEY_ALGORITHM);

  InputStream is = null;
  OutputStream out = null;
  CipherOutputStream cos = null;
  try {
   Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
   cipher.init(Cipher.DECRYPT_MODE, secretKey);
   is = new FileInputStream(fromFile);
   out = new FileOutputStream(toFile);
   cos = new CipherOutputStream(out, cipher);
   byte[] buffer = new byte[1024];
   int r;
   while ((r = is.read(buffer)) >= 0) {
    cos.write(buffer, 0, r);
   }
  } catch (Exception e) {
   KLog.e(e.toString());
  } finally {
   try {
    if (cos != null) {
     cos.close();
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
   try {
    if (out != null) {
     out.close();
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
   try {
    if (is != null) {
     is.close();
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
  }

  KLog.i("decrypt completed");
 }
}