Added some minor tweaks, and set up the EmployeeController to be usable by a frontend to see how well all this works so far.

SecureCore/Authentication/SessionManager.cs

@@ -1,12 +1,14 @@
 using System;
 using System.Data;
 using System.Data.SqlClient;
+using Microsoft.AspNetCore.Http;
 
 namespace SecureCore.Authentication
 {
     public static class SessionManager
     {
         private static int SessionKeySize { get; } = 64; //n bytes
+        public static string SessionCookieName { get; } = "Session";
 
         public static string CreateSessionToken()
         {
@@ -32,6 +34,15 @@ namespace SecureCore.Authentication
             return Convert.ToBoolean(result);
         }
 
+        public static bool IsSessionTokenValid(HttpContext context)
+        {
+            AppSettingsManager.TryGetConnectionStringByName("MainDataConnectionString", out string connectionString);
+
+            if (!context.Request.Cookies.ContainsKey(SessionCookieName)) return false;
+
+            return IsSessionTokenValid(context.Request.Cookies[SessionCookieName], connectionString);
+        }
+
         public static void Logout(string sessionToken, string connectionString)
         {
             using var connection = new SqlConnection(connectionString);