AES256

AES256.java

package com.smart.project.photo.biz;

import org.springframework.stereotype.Service;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;

@Service
public class AES256 {
    public static String alg = "AES/CBC/PKCS5Padding";
    private final String key = "01234567890123456789012345678901";
    private final String iv = key.substring(0, 16);

    public String encrypt(String text) throws Exception {
        Cipher cipher = Cipher.getInstance(alg);
        SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), "AES");
        IvParameterSpec ivParamSpec = new IvParameterSpec(iv.getBytes());
        cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivParamSpec);

        byte[] encrypted = cipher.doFinal(text.getBytes("UTF-8"));
        return Base64.getUrlEncoder().encodeToString(encrypted);
    }

    public String decrypt(String cipherText) throws Exception {
        Cipher cipher = Cipher.getInstance(alg);
        SecretKeySpec keySpec = new SecretKeySpec(key.getBytes(), "AES");
        IvParameterSpec ivParamSpec = new IvParameterSpec(iv.getBytes());
        cipher.init(Cipher.DECRYPT_MODE, keySpec, ivParamSpec);

        byte[] decodedBytes = Base64.getUrlDecoder().decode(cipherText);
        byte[] decrypted = cipher.doFinal(decodedBytes);
        return new String(decrypted, "UTF-8");
    }

}

• AES/CBC/PKCS5Padding -- 암호화 방식
• key -- 비밀 키 번호
• iv -- 바이트

AES

• 대칭키 암호화(암호화, 복호화 키 동일)
• 블록 암호

 

사용 이유

• 브라우저에 이미지 등 서버 URL노출을 막아줌
• 중요 정보를 DB에 넣을 때도 사용가능