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LFP_Manager/Function/CsCryptoHelper.cs

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+using System;
+using System.IO;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace LFP_Manager.Function
+{
+    class CsCryptoHelper
+    {
+        // 고정 키 및 IV (보안상 실제 사용 시 안전하게 관리 필요)
+        private static readonly string key = "1234567890123456"; // 16글자 = 128bit
+        private static readonly string iv = "6543210987654321";  // 16글자 = 128bit
+
+        public static string Encrypt(string plainText)
+        {
+            using (Aes aesAlg = Aes.Create())
+            {
+                aesAlg.Key = Encoding.UTF8.GetBytes(key);
+                aesAlg.IV = Encoding.UTF8.GetBytes(iv);
+
+                ICryptoTransform encryptor = aesAlg.CreateEncryptor();
+
+                using (MemoryStream msEncrypt = new MemoryStream())
+                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
+                using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
+                {
+                    swEncrypt.Write(plainText);
+                    swEncrypt.Close();
+                    return Convert.ToBase64String(msEncrypt.ToArray());
+                }
+            }
+        }
+
+        public static string Decrypt(string cipherText)
+        {
+            using (Aes aesAlg = Aes.Create())
+            {
+                aesAlg.Key = Encoding.UTF8.GetBytes(key);
+                aesAlg.IV = Encoding.UTF8.GetBytes(iv);
+
+                ICryptoTransform decryptor = aesAlg.CreateDecryptor();
+
+                byte[] buffer = Convert.FromBase64String(cipherText);
+
+                using (MemoryStream msDecrypt = new MemoryStream(buffer))
+                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
+                using (StreamReader srDecrypt = new StreamReader(csDecrypt))
+                {
+                    return srDecrypt.ReadToEnd();
+                }
+            }
+        }
+    }
+}