[java] AES256 암호화

https://github.com/Woniper/JavaExample/tree/master/AES256

1. commons-codec-1.9.jar 추가

commons-codec-1.9.jar

2. AES256 구현

package com.woniper.aes;

import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;

public class AES256Util {
	private String iv;
    private Key keySpec;

    public AES256Util(String key) throws UnsupportedEncodingException {
        this.iv = key.substring(0, 16);

        byte[] keyBytes = new byte[16];
        byte[] b = key.getBytes("UTF-8");
        int len = b.length;
        if(len > keyBytes.length)
            len = keyBytes.length;
        System.arraycopy(b, 0, keyBytes, 0, len);
        SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");

        this.keySpec = keySpec;
    }

    // 암호화
    public String aesEncode(String str) throws java.io.UnsupportedEncodingException, NoSuchAlgorithmException, 
                                                     NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, 
                                                     IllegalBlockSizeException, BadPaddingException{
        Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
        c.init(Cipher.ENCRYPT_MODE, keySpec, new IvParameterSpec(iv.getBytes()));

        byte[] encrypted = c.doFinal(str.getBytes("UTF-8"));
        String enStr = new String(Base64.encodeBase64(encrypted));

        return enStr;
    }

    //복호화
    public String aesDecode(String str) throws java.io.UnsupportedEncodingException, NoSuchAlgorithmException, 
                                                     NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, 
                                                     IllegalBlockSizeException, BadPaddingException {
        Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
        c.init(Cipher.DECRYPT_MODE, keySpec, new IvParameterSpec(iv.getBytes("UTF-8")));

        byte[] byteStr = Base64.decodeBase64(str.getBytes());

        return new String(c.doFinal(byteStr),"UTF-8");
    }
}

3. TEST 

package com.woniper.aes;

public class MainAES {

	public static void main(String[] args) throws Exception {
		String key = "aes256-test-key!!"; 		// key는 16자 이상 
		AES256Util aes256 = new AES256Util(key);
		
		String text = "암호화되지 않은 문자입니다.";
		String encText = aes256.aesEncode(text);
		String decText = aes256.aesDecode(encText);
		
		System.out.println("암호화할 문자 : " + text);
		System.out.println("암호화된 문자 : " + encText);
		System.out.println("복호화된 문자 : " + decText);
	}

}

4. 출력 결과