packagecom.kongxincai.encanddec;importjava.security.Key;importjava.security.NoSuchAlgorithmException;importjavax.crypto.Cipher;importjavax.crypto.KeyGenerator;importjavax.crypto.SecretKey;importjavax.crypto.spec.SecretKeySpec;public classAESCoder {private static final String KEY_ALGORITHM = "AES";private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";//預設的加密算法
public static byte[] initSecretKey() {//傳回生成指定算法密鑰生成器的 KeyGenerator 對象
KeyGenerator kg = null;try{
kg=KeyGenerator.getInstance(KEY_ALGORITHM);
}catch(NoSuchAlgorithmException e) {
e.printStackTrace();return new byte[0];
}//初始化此密鑰生成器，使其具有确定的密鑰大小//AES 要求密鑰長度為 128
kg.init(128);//生成一個密鑰
SecretKey secretKey =kg.generateKey();returnsecretKey.getEncoded();
}private static Key toKey(byte[] key){//生成密鑰
return newSecretKeySpec(key, KEY_ALGORITHM);
}public static byte[] encrypt(byte[] data,Key key) throwsException{returnencrypt(data, key,DEFAULT_CIPHER_ALGORITHM);
}public static byte[] encrypt(byte[] data,byte[] key) throwsException{returnencrypt(data, key,DEFAULT_CIPHER_ALGORITHM);
}public static byte[] encrypt(byte[] data,byte[] key,String cipherAlgorithm) throwsException{//還原密鑰
Key k =toKey(key);returnencrypt(data, k, cipherAlgorithm);
}public static byte[] encrypt(byte[] data,Key key,String cipherAlgorithm) throwsException{//執行個體化
Cipher cipher =Cipher.getInstance(cipherAlgorithm);//使用密鑰初始化，設定為加密模式
cipher.init(Cipher.ENCRYPT_MODE, key);//執行操作
returncipher.doFinal(data);
}public static byte[] decrypt(byte[] data,byte[] key) throwsException{returndecrypt(data, key,DEFAULT_CIPHER_ALGORITHM);
}public static byte[] decrypt(byte[] data,Key key) throwsException{returndecrypt(data, key,DEFAULT_CIPHER_ALGORITHM);
}public static byte[] decrypt(byte[] data,byte[] key,String cipherAlgorithm) throwsException{//還原密鑰
Key k =toKey(key);returndecrypt(data, k, cipherAlgorithm);
}public static byte[] decrypt(byte[] data,Key key,String cipherAlgorithm) throwsException{//執行個體化
Cipher cipher =Cipher.getInstance(cipherAlgorithm);//使用密鑰初始化，設定為解密模式
cipher.init(Cipher.DECRYPT_MODE, key);//執行操作
returncipher.doFinal(data);
}private static String showByteArray(byte[] data){if(null ==data){return null;
}
StringBuilder sb= new StringBuilder("{");for(byteb:data){
sb.append(b).append(",");
}
sb.deleteCharAt(sb.length()-1);
sb.append("}");returnsb.toString();
}public static void main(String[] args) throwsException {byte[] key =initSecretKey();
System.out.println("key："+showByteArray(key));
Key k= toKey(key); //生成秘鑰
String data ="AES資料";
System.out.println("加密前資料: string:"+data);
System.out.println("加密前資料: byte[]:"+showByteArray(data.getBytes()));
System.out.println();byte[] encryptData = encrypt(data.getBytes(), k);//資料加密
System.out.println("加密後資料: byte[]:"+showByteArray(encryptData));//System.out.println("加密後資料: hexStr:"+Hex.encodeHexStr(encryptData));
System.out.println();byte[] decryptData = decrypt(encryptData, k);//資料解密
System.out.println("解密後資料: byte[]:"+showByteArray(decryptData));
System.out.println("解密後資料: string:"+newString(decryptData));
}
}