Java AES Encrypt & Decrypt Example(加解密)

範例程式

//欲加密的字串
String msg = "This is a message.";
System.out.println("原始字串："+new String(msg));
//設定要使用的加密演算法
KeyGenerator keyG = KeyGenerator.getInstance("AES");
//設定key的長度
keyG.init(256);
//產生SecretKey
SecretKey secuK = keyG.generateKey();
//取得要用來加密的key(解密也需使用這把key)
byte[] key = secuK.getEncoded();
System.out.println("key："+new String(key));
SecretKeySpec spec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES");
//設定為加密模式
cipher.init(Cipher.ENCRYPT_MODE, spec);
//將字串加密，並取得加密後的資料
byte[] encryptData = cipher.doFinal(msg.getBytes());
System.out.println("加密後字串："+new String(encryptData));

//使用剛剛用來加密的key進行解密
spec = new SecretKeySpec(key, "AES");
cipher = Cipher.getInstance("AES");
//設定為解密模式
cipher.init(Cipher.DECRYPT_MODE, spec);
byte[] original = cipher.doFinal(encryptData);
System.out.println("解密後字串："+new String(original));

輸出結果

原始字串：This is a message.
key：�U{� jPk ���@7 .�A@��&]W LK���ݣ
加密後字串：��� � ����tl7Q U!���d�{4R) �� .
解密後字串：This is a message.