자바 암호화와 복호화(AES)

AES 란?

AES는 고급 암호화 표준이라는 의미이며, 암호화 및 복호화 시 동일한 키를 사용하는 대칭키 알고리즘
AES의 종류는 AES-128, AES-192, AES-256이 있고 각각 뒤에 붙은 숫자가 키의 길이를 의미함
AES 암호화 알고리즘은 높은 안정성과 빠른 속도로 전세계적으로 사용되고 있음

 

 

암호화 복호화 예제 👇

package com.nmn.deploy.util;

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");
  }

 

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참고 자료 

https://bgc8214.github.io/%EC%95%88%EB%93%9C%EB%A1%9C%EC%9D%B4%EB%93%9C/2019/01/03/%EC%9E%90%EB%B0%94-%EC%95%94%ED%98%B8%EC%99%80-(AES).html