Java AES加密解密實現基礎教程

本文總結Java AES加密解密應用實例，Java加密解密庫都很完善，所以，調用方法也都非常簡單，但Java代碼以低效率著稱，所以，對時效性要求太高的盡量避開Java層而使用C/C++等程序實現。C/C++ AES算法實現可參考天緣前一篇文章《AES CBC和CTR加解密實例》。

基礎知識，AES模式區別：AES CFB/OFB/ECB/CBC/CTR優缺點

Java示例代碼如下：

默認使用AES128 ECB/NoPadding，具體參數設置可參考文末地址。因為是NoPadding，所以，要求輸入的數據長度必須為16Byte倍數。如果使用CBC模式，還需附帶IV參量。

import java.security.SecureRandom;
import java.security.Key;
import java.security.Security;

import javax.crypto.SecretKey;  
import javax.crypto.SecretKeyFactory;
import javax.crypto.KeyGenerator;
import javax.crypto.Cipher;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.spec.IvParameterSpec;

//AES 128
public class ComCipher {
	private byte[] btAESKey	= new byte[16];//128 bits AES
	private Cipher 		  cObj;
	private SecretKeySpec 	sAesKey;
	
	public ComCipher(){
		int i=0;
		for(i=0;i<16;i++)
			btAESKey[i]=0x01;
	}

	public void AESInit()  throws Exception{
		sAesKey  = new SecretKeySpec(btAESKey, "AES");
		cObj = Cipher.getInstance("AES/ECB/NoPadding");//NoPadding PKCS5Padding
	}
	
    //AES Encrypt content
    public byte[] AESEncrypt(byte[] btCont)  throws Exception {
       	cObj.init(Cipher.ENCRYPT_MODE, sAesKey);
        return cObj.doFinal(btCont);
    }	

    //AES Decrypt content 
    public byte[] AESDecrypt(byte[] btCont)  throws Exception {
    	cObj.init(Cipher.DECRYPT_MODE, sAesKey);
        return cObj.doFinal(btCont);
    }	
	
}

用法如下：

	ComCipher ObjCipher = new ComCipher();
	try {
		int iLen=8;
		byte[] c1 = new byte[iLen];
		for(int k=0;k<iLen;k++)
			c1[k]=0x01;
		ObjCipher.AESInit();
	        byte[] resC = ObjCipher.AESEncrypt(c1);
		System.out.println("AESEnc:"+HexToString(resC,resC.length));
	        byte[] resD = ObjCipher.AESDecrypt(resA);
		System.out.println("AESDec:"+HexToString(resD,resD.length));
	 } catch (Exception e1) {
            e1.printStackTrace();
	 }	

上述代碼中，HexToString打印Byte數組到字符串，源碼略。