Android AES(128, 192, 256) 암복호화

AES 암복호화

• key값의 길이에 따라 AES128, AES192, AES256 으로 구분됨
  • AES128 : 키값 16bytes
  • AES192 : 키값 24bytes
  • AES256 : 키값 32bytes

 

예제 코드(AES256)

import android.util.Base64;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
 
public class AES256Util {
    //키값 32바이트: AES256(24: AES192, 16: AES128)
    public static String secretKey = "01234567890123450123456789012345";
    public static byte[] ivBytes = "0123456789012345".getBytes();
 
    //AES256 암호화
    public static String aesEncode(String str) {
        try {
            byte[] textBytes = str.getBytes("UTF-8");
            AlgorithmParameterSpec ivSpec = new IvParameterSpec(ivBytes);
            SecretKeySpec newKey = new SecretKeySpec(secretKey.getBytes("UTF-8"), "AES");
            Cipher cipher = null;
            cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, newKey, ivSpec);
 
            return Base64.encodeToString(cipher.doFinal(textBytes), Base64.DEFAULT);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
 
    //AES256 복호화
    public static String aesDecode(String str) {
        try {
            byte[] textBytes = Base64.decode(str, Base64.DEFAULT);
            AlgorithmParameterSpec ivSpec = new IvParameterSpec(ivBytes);
            SecretKeySpec newKey = new SecretKeySpec(secretKey.getBytes("UTF-8"), "AES");
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, newKey, ivSpec);
 
            return new String(cipher.doFinal(textBytes), "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return str;
    }
}