无法克服 javax.crypto.BadPaddingException

Question

我正在编写一个加密图像中文本的隐写术系统 - 我决定在将文本嵌入图片之前也对文本进行加密。隐写术算法适用于字符串 input/output.

由于一时兴起，我一直在尝试使用 DES 和 AES 算法，但运行进入了上面的异常。例如，我将展示 AES 算法的 encryption/decryption 方法：

    public static byte[] encryptText(String plainText,SecretKey secKey) throws Exception{
    // AES defaults to AES/ECB/PKCS5Padding in Java 7
    Cipher aesCipher = Cipher.getInstance("AES");
    aesCipher.init(Cipher.ENCRYPT_MODE, secKey);
    byte[] byteCipherText = aesCipher.doFinal(plainText.getBytes());
    return byteCipherText;}


    public static String decryptText(byte[] byteCipherText, SecretKey secKey) throws Exception {
    // AES defaults to AES/ECB/PKCS5Padding in Java 7
    Cipher aesCipher = Cipher.getInstance("AES");
    aesCipher.init(Cipher.DECRYPT_MODE, secKey);
    byte[] bytePlainText = aesCipher.doFinal(byteCipherText);
    return new String(bytePlainText);
}

这是调用（加密端）：

  //sending the text to encrypt using AES algorithm
byte[] cipherText = new AES_Algorithm().encrypt(messageDesc.getText(), key);
  //converting into a String to encrypt using Steganography
newStringtoEncrypt = new String (cipherText);

这是调用（解密方）- 异常：

  //AES encrypted String after the Steganography's decryption 
String decMessage = dec.decode(path, name);
  //converting the String to byte []
byte [] byteArray = decMessage.getBytes();
try{
    //HERE IS WHERE I GET THE EXCEPTION
    //sending the byte array to decryption
  String original = AES_Algorithm().decrypt(byteArray, key);

问题出在哪里？

键很相似，字节数组也很相似（我通过打印序列来检查它）——但我被告知我不能使用 getBytes() 来从字符串转换为 byteArray当我打算使用AES/DES解密算法时。

Answer 1

加密的输出是二进制的，您不能像在以下代码中那样将其转换为 String：

byte[] cipherText = new AES_Algorithm().encrypt(messageDesc.getText(), key);
//converting into a String to encrypt using Steganography
newStringtoEncrypt = new String (cipherText);

如果您需要String这样的加密数据，您需要以某种方式对其进行编码，例如通过 base64encoding or by hexEncoding

无法克服 javax.crypto.BadPaddingException

Can't overcome the javax.crypto.BadPaddingException

java

encryption

cryptography

steganography

badpaddingexception