AES 256加密问题

本文介绍了AES 256加密问题的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 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>

www.oracle/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:

www.oracle/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.