AES 256加密问题 [英] AES 256 Encryption Issue

问题描述

以下代码完美地实现了AES-128加密/解密。

  public static void main（String [] args）throws异常
 {
 String input = JOptionPane.showInputDialog（null，Enter your String）; 
 System.out.println（Plaintext：+ input +\\\
）; 
 
 //生成密钥
 KeyGenerator keygen = KeyGenerator.getInstance（AES）; 
 keygen.init（128）; 
 byte [] key = keygen.generateKey（）。getEncoded（）; 
 SecretKeySpec skeySpec = new SecretKeySpec（key，AES）; 
 
 //随机生成IV 
 SecureRandom random = new SecureRandom（）; 
 byte [] iv = new byte [16]; 
 random.nextBytes（iv）; 
 IvParameterSpec ivspec = new IvParameterSpec（iv）; 
 
 //初始化加密模式
密码加密= Cipher.getInstance（AES / CBC / PKCS5Padding）; 
 cipher.init（Cipher.ENCRYPT_MODE，skeySpec，ivspec）; 
 
 //加密消息
 byte [] encryption = cipher.doFinal（input.getBytes（））; 
 System.out.println（Ciphertext：+ encryption +\\\
）; // 
 
 //初始化用于解密的密码
 cipher.init（Cipher.DECRYPT_MODE，skeySpec，ivspec）; 
 
 //解密消息
 byte [] decrypt = cipher.doFinal（encryption）; 
 System.out.println（Plaintext：+ new String（decrypt）+\\\
）; 
} 
  

当我要使用AES-256时，我认为可以通过只是修改 keygen.init（256）; 和 byte [] iv = new byte [32]; 变为错误（线程主中的异常java.security.InvalidKeyException：非法密钥大小）！有人可以解释为什么错误发生时，我做这两个修改，我该怎么办。 ）

解决方案

如果要使用AES 256加密，必须安装无限制强度管辖权政策文件： p>

http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html

这启用

使用< java-home> \\中的当前文件替换zip中的文件。 \\ lib \security 。

The following code perfectly implements AES-128 encryption/decryption.

public static void main(String[] args) throws Exception
{
    String input = JOptionPane.showInputDialog(null, "Enter your String");
    System.out.println("Plaintext: " + input + "\n");

    // Generate a key
    KeyGenerator keygen = KeyGenerator.getInstance("AES");
    keygen.init(128); 
    byte[] key = keygen.generateKey().getEncoded();
    SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");

    // Generate IV randomly
    SecureRandom random = new SecureRandom();
    byte[] iv = new byte[16];
    random.nextBytes(iv);
    IvParameterSpec ivspec = new IvParameterSpec(iv);

    // Initialize Encryption Mode
    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec, ivspec);

    // Encrypt the message
    byte[] encryption = cipher.doFinal(input.getBytes());
    System.out.println("Ciphertext: " + encryption + "\n"); //

    // Initialize the cipher for decryption
    cipher.init(Cipher.DECRYPT_MODE, skeySpec, ivspec);

    // Decrypt the message
    byte[] decryption = cipher.doFinal(encryption);
    System.out.println("Plaintext: " + new String(decryption) + "\n");
}

When I want to use AES-256, I thought that can be done by just modifying keygen.init(256); and byte[] iv = new byte[32];, however this becomes error (Exception in thread "main" java.security.InvalidKeyException: Illegal key size)! Can someone explain why error occurs when I made these two modification and what should I do. Thank you guys :)

解决方案

If you want to use AES 256 encryption you must install the Unlimited Strength Jurisdiction Policy Files:

http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html

This enables the higher encryption levels like AES 256 and RSA 2048.

Replace the files from the zip with the current ones in <java-home>\lib\security.

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