ASP.NET MVC : RijndaelManaged CBC, Pkcs7 암호화 및 복호화 라이브러리 함수

 

ASP.NET MVC : CBC, Pkcs7 암호화 및 복호화 라이브러리 함수

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Web;

namespace WebApp48.Helpers
{
    public static class Utility
    {
        public static string DecryptStringAES(string cipherText)
        {

            var keybytes = Encoding.UTF8.GetBytes("8080808080808080");
            var iv = Encoding.UTF8.GetBytes("8080808080808080");

            var encrypted = Convert.FromBase64String(cipherText);
            var decriptedFromJavascript = DecryptStringFromBytes(encrypted, keybytes, iv);
            return string.Format(decriptedFromJavascript);
        }

        private static string DecryptStringFromBytes(byte[] cipherText, byte[] key, byte[] iv)
        {
            // Check arguments.
            if (cipherText == null || cipherText.Length <= 0)
            {
                throw new ArgumentNullException("cipherText");
            }
            if (key == null || key.Length <= 0)
            {
                throw new ArgumentNullException("key");
            }
            if (iv == null || iv.Length <= 0)
            {
                throw new ArgumentNullException("key");
            }

            // Declare the string used to hold
            // the decrypted text.
            string plaintext = null;

            // Create an RijndaelManaged object
            // with the specified key and IV.
            using (var rijAlg = new RijndaelManaged())
            {
                //Settings
                rijAlg.Mode = CipherMode.CBC;
                rijAlg.Padding = PaddingMode.PKCS7;
                rijAlg.FeedbackSize = 128;

                rijAlg.Key = key;
                rijAlg.IV = iv;

                // Create a decrytor to perform the stream transform.
                var decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
                try
                {
                    // Create the streams used for decryption.
                    using (var msDecrypt = new MemoryStream(cipherText))
                    {
                        using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                        {

                            using (var srDecrypt = new StreamReader(csDecrypt))
                            {
                                // Read the decrypted bytes from the decrypting stream
                                // and place them in a string.
                                plaintext = srDecrypt.ReadToEnd();

                            }

                        }
                    }
                }
                catch
                {
                    plaintext = "keyError";
                }
            }

            return plaintext;
        }

        public static byte[] EncryptStringToBytes(string plainText, byte[] key, byte[] iv)
        {
            // Check arguments.
            if (plainText == null || plainText.Length <= 0)
            {
                throw new ArgumentNullException("plainText");
            }
            if (key == null || key.Length <= 0)
            {
                throw new ArgumentNullException("key");
            }
            if (iv == null || iv.Length <= 0)
            {
                throw new ArgumentNullException("key");
            }
            byte[] encrypted;
            // Create a RijndaelManaged object
            // with the specified key and IV.
            using (var rijAlg = new RijndaelManaged())
            {
                rijAlg.Mode = CipherMode.CBC;
                rijAlg.Padding = PaddingMode.PKCS7;
                rijAlg.FeedbackSize = 128;

                rijAlg.Key = key;
                rijAlg.IV = iv;

                // Create a decrytor to perform the stream transform.
                var encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);

                // Create the streams used for encryption.
                using (var msEncrypt = new MemoryStream())
                {
                    using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (var swEncrypt = new StreamWriter(csEncrypt))
                        {
                            //Write all data to the stream.
                            swEncrypt.Write(plainText);
                        }
                        encrypted = msEncrypt.ToArray();
                    }
                }
            }

            // Return the encrypted bytes from the memory stream.
            return encrypted;
        }
    }
}

 

javascript 에서 CBC, Pkcs7 으로 암호화 처리

 

중요한것은 "https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/rollups/aes.js" 를 활용하여 암호화작업을 스크립트 단에서 작업이 가능하다는 점입니다.

 

<script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.2/rollups/aes.js"></script>
<script type="text/javascript">
    $(function () {
        $("#btnSave").click(function () {

            var enc1 = '==냠냠?test=&jcop=test&동해물과 + + 백두산이 마르고 닳도록 abcdefghijh ~!@@#$%^&*()_+|<>?"';

            var key = CryptoJS.enc.Utf8.parse('8080808080808080');
            var iv = CryptoJS.enc.Utf8.parse('8080808080808080');
            var encryptedlogin = CryptoJS.AES.encrypt(CryptoJS.enc.Utf8.parse(enc1), key,
                { keySize: 128 / 8, iv: iv, mode: CryptoJS.mode.CBC, padding: CryptoJS.pad.Pkcs7 });
            var enc = encryptedlogin;
            console.log(enc);


            $.ajax({
                type: "POST",
                url: '@Url.Action("GetData")',
                data: JSON.stringify({enc: '' + enc + ''}),
                dataType: "json",
                contentType: "application/json; charset=utf-8",
                success: function () {
                    alert("Data has been added successfully.");
                },
                error: function () {
                    alert("Error while inserting data");
                }
            });
            return false;
        });
    });
</script>
<h2>Index</h2>
<input type="button" name="Save" value="Save" id="btnSave" />

 

jQuery 의 ajax 통신에 대한 backend 단 기술 부분 입니다.

public JsonResult GetData(string enc)
{
  var DecryptVal = Utility.DecryptStringAES(enc);            
  return Json(DecryptVal, JsonRequestBehavior.AllowGet);
}

 

끝~

 

 

asp.net mvc 의 c# 에서 CBC, Pkcs7 암호화 및 복호화

 

스크립트의 라이브러리 도움없이 backend 단에서도 암복호화 가능합니다. 

public ActionResult Index()
{
  var rawData = "==냠냠?test=&jcop=test&동해물과 + + 백두산이 마르고 닳도록 abcdefghijh ~!@#$%^&*()_+|<>?";

  var key = Encoding.UTF8.GetBytes("8080808080808080");
  var iv = Encoding.UTF8.GetBytes("8080808080808080");
  var encByte = Utility.EncryptStringToBytes(rawData, key, iv);
  var encString = Convert.ToBase64String(encByte, 0, encByte.Length);
  var decryptVal = Utility.DecryptStringAES(encString);

  return View();
}

 

 

참고 사이트

 

1> Encrypt in javascript and pass it into Ajax call and decrypt in MVC Controller using AES Algorithm

https://www.coreprogramm.com/2021/01/encrypt-in-javascript-pass-data-in-ajax-call-decrypt-controller.html

Encrypt in javascript and pass it into Ajax call and decrypt in MVC Controller using AES Algorithm

 

2> c# - .NET에서 문자열을 암호화하는 방법은 무엇입니까?

https://pythonq.com/so/c%23/424144

c# - .NET에서 문자열을 암호화하는 방법은 무엇입니까? [복제] - IT 툴 넷

 

3> CryptoJS decrypt object

https://stackoverflow.com/a/50328007

CryptoJS decrypt object

 

 

 

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아래 사이트도 많이 도움이 될겁니다. 중복된 블로그 글 같네요.. ~ ^^;;

C# 의 AES/CBC/PKCS5Padding 으로 암복호화 하기

C# 의 AES/CBC/PKCS5Padding 으로 암복호화 하기