using System.Security.Cryptography;
using System.Text.RegularExpressions;
public static void Main()
string originalText = "102";
string key = "ThisIsA16ByteKey";
string encryptedText = EncryptAes(originalText, key);
string truncatedEncryptedText = RemoveSpecialSymbols(encryptedText.Substring(0, 9));
Console.WriteLine("Original Text: " + originalText);
Console.WriteLine("Truncated Encrypted Text: " + truncatedEncryptedText);
public static string EncryptAes(string plainText, string key)
using Aes aesAlg = Aes.Create();
aesAlg.Key = Encoding.UTF8.GetBytes(key);
aesAlg.Mode = CipherMode.ECB;
aesAlg.Padding = PaddingMode.PKCS7;
ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, null);
using MemoryStream msEncrypt = new MemoryStream();
using CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write);
using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
swEncrypt.Write(plainText);
byte[] encryptedBytes = msEncrypt.ToArray();
return Convert.ToBase64String(encryptedBytes);
public static string RemoveSpecialSymbols(string input)
string pattern = "[@#$!+/]";
string sanitized = Regex.Replace(input, pattern, string.Empty);