AES

import java.math.BigInteger;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

public class AES {

public static void main(String[] args) throws Exception {

AES main = new AES();

SecretKey key = main.generateSecretKey();

String message = "암호화 테스트";

System.out.println("암호전 : " + message);

String encrypted = main.encrypt(message, key);

System.out.println("암호화 : " + encrypted);

String decrypted = main.decrypt(encrypted, key);

System.out.println("복호화 : " + decrypted);

}

public SecretKey generateSecretKey() throws Exception {

KeyGenerator keygen = KeyGenerator.getInstance("AES");

keygen.init(128);

SecretKey skey = keygen.generateKey();

return skey;

}

public String encrypt(String message, SecretKey key) throws Exception {

SecretKeySpec skeySpec = new SecretKeySpec(key.getEncoded(), "AES");

Cipher cipher = Cipher.getInstance("AES");

cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

byte[] encrypted = cipher.doFinal(message.getBytes());

return new BigInteger(encrypted).toString(16);

}

public String decrypt(String encrypted, SecretKey key) throws Exception {

SecretKeySpec skeySpec = new SecretKeySpec(key.getEncoded(), "AES");

Cipher cipher = Cipher.getInstance("AES");

cipher.init(Cipher.DECRYPT_MODE, skeySpec);

byte[] decrypted = cipher.doFinal(new BigInteger(encrypted, 16).toByteArray());

return new String(decrypted);

}

}