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Java AES256 Sample 코드.

06 Dec 2018 | Java AES256 암호화

AES 란?

Advanced Encryption Standard를 줄인 말이다. 한국어로 번역하면 ‘고급 암호화 표준’이다. 대칭키를 쓰는 블럭 암호이다. 높은 안전성과 속도로 인해 인기를 얻어 전 세계적으로 많이 사용되고 있다.

특징

대칭형, 블럭 암호화 알고리즘이다.
대칭형 암호화 알고리즘 중 가장 유명하다.
암호화 키는 128, 192, 256의 세 가지 중 하나가 될 수 있으며, 각각 AES-128, AES-192, AES-256으로 불린다.

AES256Cipher.java

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidAlgorithmParameterException;

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

public class AES256Cipher {

    private static volatile AES256Cipher INSTANCE;

    final static String secretKey = "jmlim12345bbbbbaaaaa123456789066"; //32bit
    static String IV = ""; //16bit

    public static AES256Cipher getInstance() {
        if (INSTANCE == null) {
            synchronized (AES256Cipher.class) {
                if (INSTANCE == null)
                    INSTANCE = new AES256Cipher();
            }
        }
        return INSTANCE;
    }

    private AES256Cipher() {
        IV = secretKey.substring(0, 16);
    }

    //암호화
    public static String AES_Encode(String str) throws java.io.UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
        byte[] keyData = secretKey.getBytes();

        SecretKey secureKey = new SecretKeySpec(keyData, "AES");

        Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
        c.init(Cipher.ENCRYPT_MODE, secureKey, new IvParameterSpec(IV.getBytes()));

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

        return enStr;
    }

    //복호화
    public static String AES_Decode(String str) throws java.io.UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
        byte[] keyData = secretKey.getBytes();
        SecretKey secureKey = new SecretKeySpec(keyData, "AES");
        Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
        c.init(Cipher.DECRYPT_MODE, secureKey, new IvParameterSpec(IV.getBytes("UTF-8")));

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

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

AES256CipherTest.java


import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

import org.junit.Test;

public class AES256CipherTest {
    String id = "hackerljm";
    String custrnmNo = "1234";
    String custNm = "정묵테스트";

    @Test
    public void encDesTest() throws InvalidKeyException, UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidAlgorithmParameterException, IllegalBlockSizeException, BadPaddingException {
        AES256Cipher a256 = AES256Cipher.getInstance();

        String enId = a256.AES_Encode(id);
        String enYyyymmdd = a256.AES_Encode(custrnmNo);
        String enCustNm = a256.AES_Encode(custNm);

        String desId = a256.AES_Decode(enId);
        String desYyyymmdd = a256.AES_Decode(enYyyymmdd);
        String desCustNm = a256.AES_Decode(enCustNm);

        assertThat(id, is(desId));
        assertThat(custrnmNo, is(desYyyymmdd));
        assertThat(custNm, is(desCustNm));
    }
}

참고:

  • https://dukeom.wordpress.com/2013/01/08/aes256-%EC%95%94%ED%98%B8%ED%99%94-java-%EC%83%98%ED%94%8C/
  • https://namu.wiki/w/AES

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