java - 使用 AES-CBC-PKCS5Padding 解密数据时出现填充错误

Question

我编写了如下两个函数来加密和解密数据。

public static void encrypt() throws Exception {
    // Add the BouncyCastle Provider
    //Security.addProvider(new BouncyCastleProvider());


// Generate the key
byte[] keyBytes = "AAAAAAAAAAAAAAAA".getBytes();
SecretKeySpec   key = new SecretKeySpec(keyBytes, "AES");

// Generate the IV
byte[] ivBytes  = "AAAAAAAAAAAAAAAA".getBytes();
IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);

// Create the cipher object and initialize it
Cipher          cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, ivSpec);

// Read all bytes from a file into a bytes array
byte[] inputBytes = GCM.readFile("input");
byte[] cipherBytes = cipher.doFinal(inputBytes);

BufferedOutputStream  outputStream = new BufferedOutputStream(new FileOutputStream("output.enc"));
outputStream.write(cipherBytes);

outputStream.close();   
}

public static void decrypt() throws Exception {
    // Add the BouncyCastle Provider
     //Security.addProvider(new BouncyCastleProvider());

 // Generate the key
 byte[] keyBytes = "AAAAAAAAAAAAAAAA".getBytes();
 SecretKeySpec   key = new SecretKeySpec(keyBytes, "AES");

 // Generate the IV
 byte[] ivBytes  = "AAAAAAAAAAAAAAAA".getBytes();
 IvParameterSpec ivSpec = new IvParameterSpec(ivBytes);

 // Create the cipher object and initialize it
 Cipher          cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
 cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);

 // Read all bytes from a file into a bytes array
 byte[] cipherBytes = GCM.readFile("ouput.enc");
 byte[] decBytes = cipher.doFinal(cipherBytes);

 BufferedOutputStream  outputStream = new BufferedOutputStream(new FileOutputStream("regen.plain"));
 outputStream.write(decBytes);
 outputStream.close();   
}

我意识到代码的 key 设置为 "AAAAAAAAAAAAAAAA".getBytes() ；但是请耐心等待，因为这只是一个例子。

当我运行程序时，我得到以下堆栈跟踪:-

Exception in thread "main" javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
    at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
    at GCM.decrypt(GCM.java:80)
    at GCM.main(GCM.java:90)

我无法弄清楚为什么会遇到此错误。有关如何解决该问题的任何提示吗？

[编辑] 看起来，当我写出数据时，总共有16个字节，但当我读回它时，只有15个字节。

Answer 1

关于您的更新:嗯，这很简单，修复读取文件的部分，因为密文需要为 N * block 大小，即 16 字节。我没有看到任何其他明显的错误。