使用Java加密/解密AES 256密钥

问题描述：

我试图将我的应用从128位AES密钥升级到256位AES密钥。但是，当我将第54行从128更改为256时，出现以下密钥大小错误。使用Java加密/解密AES 256密钥

java.security.InvalidKeyException：非法密钥大小

我已经正确安装了JCE文件，由我的应用程序生成更长的密钥的事实所证明。

package com.company; 
import com.hazelcast.util.Base64; 
import javax.crypto.*; 
import javax.crypto.spec.*; 

class Encryption { 

    public static String encrypt (String strKey, String strIv, String str) { 
     String secret = ""; 
     try{ 
      byte[] key = Base64.decode(strKey.getBytes()); 
      byte[] iv = Base64.decode(strIv.getBytes()); 

      SecretKeySpec keyspec = new SecretKeySpec(key, "AES"); 
      IvParameterSpec ivspec = new IvParameterSpec(iv); 
      Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); 

      cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec); 
      secret = new String(Base64.encode(cipher.doFinal(str.getBytes()))); 

     } 
     catch(Exception e){ 
      e.printStackTrace(); 
     } 
     return secret; 
    } 

    public static String decrypt (String strKey, String strIv, String str) { 
     String secret = ""; 
     try{ 

      byte[] key = Base64.decode(strKey.getBytes()); 
      byte[] iv = Base64.decode(strIv.getBytes()); 


      SecretKeySpec keyspec = new SecretKeySpec(key, "AES"); 
      IvParameterSpec ivspec = new IvParameterSpec(iv); 
      Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); 

      cipher.init(Cipher.DECRYPT_MODE, keyspec,ivspec); 
      secret = new String(cipher.doFinal(new Base64().decode(str.getBytes()))); 

     } 
     catch(Exception e){ 
      e.printStackTrace(); 
     } 
     return secret; 
    } 

    public static void main(String[] argv) { 
     String strIv = "18A5Z/IsHs6g8/65sBxkCQ=="; 
     String strKey = ""; 
     int keyStrength = 256; 
     try { 
      KeyGenerator kgen = KeyGenerator.getInstance("AES"); 
      kgen.init(keyStrength); 

      SecretKey skey = kgen.generateKey(); 
      byte[] raw = skey.getEncoded(); 
      strKey = new String(new Base64().encode(raw)); 
      System.out.println("Secret key is: " + strKey); 
     } catch (Exception ex) { 
      System.out.println(ex.toString()); 
     } 
     String message = "My, it's a lovely day today!!!"; 
     String encrypted = Encryption.encrypt(strKey, strIv, message); 
     System.out.println("Encrypted string is: " + encrypted); 
     System.out.println("Decrypted string is: " + Encryption.decrypt(strKey, strIv, encrypted)); 


    } 
}

我见过的其他帖子引用 “AES/CBC/PKCS7Padding” 加密方法，但只是让我这个异常：

java.security.NoSuchAlgorithmException: Cannot find any provider supporting AES/CBC/PKCS7Padding 
    at javax.crypto.Cipher.getInstance(Cipher.java:540) 
    at com.company.Encryption.encrypt(Encryption.java:17) 
    at com.company.Encryption.main(Encryption.java:67) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:498) 
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) 
java.security.NoSuchAlgorithmException: Cannot find any provider supporting AES/CBC/PKCS7Padding 
    at javax.crypto.Cipher.getInstance(Cipher.java:540) 
    at com.company.Encryption.decrypt(Encryption.java:39) 
    at com.company.Encryption.main(Encryption.java:69) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:498) 
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

哪行引发InvalidKeyException？ –

[InvalidKeyException非法密钥大小]的可能重复（http://stackoverflow.com/questions/3862800/invalidkeyexception-illegal-key-size） –

*“我有JCE文件正确安装”* - 如果您的意思是无限强度策略文件，你真的*确定你在安装策略文件的JVM中运行代码吗？如果您不确定，那么您应该将它们安装在所有JRE中（包括全局JRE以及JDK内的JRE）。 –

答

发现...

甲骨文从技术上将JCE文件的版本标记在他们的下载页面上，但这对我来说并不明显。我正在用java 8 JRE安装java 6文件。这就是为什么我能够生成密钥但不能加密/解密的原因。

我找到了正确的文件，安装了它们，现在它正在工作。

谢谢！

使用Java加密/解密AES 256密钥

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