StringEncryptor.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace CSEmployeeAttendance25
{
    public static class StringEncryptor
    {
        private static readonly string EncryptionKey = "YourSecureKey123456"; // 🔑 Change this key!

        public static string EncryptString(string text)
        {
            byte[] keyBytes = Encoding.UTF8.GetBytes(EncryptionKey.PadRight(32, '0')); // Ensure 32-byte key
            using (Aes aes = Aes.Create())
            {
                aes.Key = keyBytes;
                aes.GenerateIV();
                byte[] iv = aes.IV;

                using (MemoryStream ms = new MemoryStream())
                {
                    ms.Write(iv, 0, iv.Length); // Prepend IV to the ciphertext

                    using (CryptoStream cs = new CryptoStream(ms, aes.CreateEncryptor(), CryptoStreamMode.Write))
                    using (StreamWriter sw = new StreamWriter(cs))
                    {
                        sw.Write(text);
                    }

                    return Convert.ToBase64String(ms.ToArray());
                }
            }
        }

        public static string DecryptString(string encryptedText)
        {
            byte[] fullCipher = Convert.FromBase64String(encryptedText);
            byte[] keyBytes = Encoding.UTF8.GetBytes(EncryptionKey.PadRight(32, '0')); // Ensure 32-byte key

            using (Aes aes = Aes.Create())
            {
                aes.Key = keyBytes;
                byte[] iv = new byte[aes.IV.Length];
                Array.Copy(fullCipher, iv, iv.Length);

                using (MemoryStream ms = new MemoryStream(fullCipher, iv.Length, fullCipher.Length - iv.Length))
                using (CryptoStream cs = new CryptoStream(ms, aes.CreateDecryptor(), CryptoStreamMode.Read))
                using (StreamReader sr = new StreamReader(cs))
                {
                    return sr.ReadToEnd();
                }
            }
        }
    }

}