[筆記] Java crypto & How to restore the key object
單純做個筆記...
import javax.crypto.KeyGenerator;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class AES {
public static void main(String[] args) throws Exception{
KeyGenerator kg = KeyGenerator.getInstance("AES");
kg.init(128); //初始化
SecretKey key = kg.generateKey(); //生成key
byte[] keyRaw = key.getEncoded(); //取得encoded key
Cipher cp = Cipher.getInstance("AES");
cp.init(Cipher.ENCRYPT_MODE, key); // 初始化為加密模式
String str = "天譴寶寶吃肉... ";
byte [] pText = str.getBytes(); // 可指定文字編碼
byte [] cText = cp.doFinal(pText); //加密
System.out.println(new String(cText)); // 加密過後的String
由encoded key，轉為key Object
SecretKeySpec keySpec = new SecretKeySpec(keyRaw, "AES");
cp.init(Cipher.DECRYPT_MODE, keySpec); // 重新初始化為解密模式
pText = cp.doFinal(cText); // 解密
String str2 = new String(pText); // 需配合加密端指定文字編碼，沒有就聽天由命
System.out.println(str2);
}
}
參考資料：
1. blog.csdn.net/xjtuse_mal/archive/2007/11/08/1874869.aspx
2. forums.sun.com/thread.jspa?threadID=760082