5 files changed, 42 insertions, 9 deletions

diff --git a/README.md b/README.md
index b8d244c..db96b7f 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,30 @@
 TwoStepsAuthenticator
 =====================
 
-.net implementation of the TOTP: Time-Based One-Time Password Algorithm - RFC 6238 http://tools.ietf.org/html/rfc6238
+.net implementation of the TOTP: Time-Based One-Time Password Algorithm<br/>
+RFC 6238 http://tools.ietf.org/html/rfc6238
 
 compatible with Microsoft Authenticator for Windows Phone, and Google Authenticator for Android and iPhone.
+
+You can use this library as well for a client application (if you want to create your own authenticator) or for a server application (add two-step authentication on your asp.net website)
+
+For a client application, you need to save the secret key for your user. <br/>
+Then, you only have to call the method GetCode(string) :
+
+<pre><code>var secret = user.secretAuthToken;
+var authenticator = new TwoStepsAuthenticator.Authenticator();
+var code = authenticator.GetCode(secret);</code></pre>
+
+On a server application, you will have to generate a secret key, and share it with the user, who will have to enter it in his own authenticator app.
+
+<pre><code>var authenticator = new TwoStepsAuthenticator.Authenticator();
+var key = authenticator.GenerateKey();</code></pre>
+
+When the user will login, he will have to give you the code generated by his authenticator.<br/>
+You can check if the code is correct with the method CheckCode(string secret, string code).<br/>
+If the code is incorrect, don't log him.
+
+<pre><code>var secret = user.secretAuthToken;
+var code = Request.Form["code"];
+var authenticator = new TwoStepsAuthenticator.Authenticator();
+var isok = authenticator.CheckCode(secret, code);</code></pre>
diff --git a/TwoStepsAuthenticator.TestApp/MainWindow.xaml.cs b/TwoStepsAuthenticator.TestApp/MainWindow.xaml.cs
index 43469af..f74a031 100644
--- a/TwoStepsAuthenticator.TestApp/MainWindow.xaml.cs
+++ b/TwoStepsAuthenticator.TestApp/MainWindow.xaml.cs
@@ -25,7 +25,6 @@ namespace TwoStepsAuthenticatorTestApp
         {
             InitializeComponent();
             model = new ViewModel();
-            model.Key="JBSWY3DPEHPK3PXP";
             this.DataContext = model;
         }
 
diff --git a/TwoStepsAuthenticator.TestApp/ViewModel.cs b/TwoStepsAuthenticator.TestApp/ViewModel.cs
index 51db3a8..8bfeb9b 100644
--- a/TwoStepsAuthenticator.TestApp/ViewModel.cs
+++ b/TwoStepsAuthenticator.TestApp/ViewModel.cs
@@ -72,8 +72,9 @@ namespace TwoStepsAuthenticatorTestApp
 
         public ViewModel()
         {
+            var authenticator = new TwoStepsAuthenticator.Authenticator();
+            this.Key = authenticator.GenerateKey();
             timer = new DispatcherTimer(TimeSpan.FromSeconds(1), DispatcherPriority.Normal, timerCallback, App.Current.Dispatcher);
-            //timer.Elapsed += timer_Elapsed;
             timer.Start();
         }
 
@@ -96,6 +97,8 @@ namespace TwoStepsAuthenticatorTestApp
         {
             var auth = new TwoStepsAuthenticator.Authenticator();
             Code = auth.GetCode(this.Key);
+
+            auth.CheckCode(key, Code);
         }
     }
 }
diff --git a/TwoStepsAuthenticator/Authenticator.cs b/TwoStepsAuthenticator/Authenticator.cs
index d196525..0f0e298 100644
--- a/TwoStepsAuthenticator/Authenticator.cs
+++ b/TwoStepsAuthenticator/Authenticator.cs
@@ -9,11 +9,18 @@ namespace TwoStepsAuthenticator
 {
     public class Authenticator
     {
-        private static UsedCodesManager usedCodes = new UsedCodesManager();
+        private static Lazy<UsedCodesManager> usedCodes = new Lazy<UsedCodesManager>();
 
         public string GenerateKey()
         {
-            throw new NotImplementedException();
+            var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
+            var random = new Random();
+            var keyChars = new char[16];
+            for (int i = 0; i < 16; i++)
+            {
+                keyChars[i] = chars[random.Next(chars.Length)];
+            }
+            return new String(keyChars);
         }
 
         public string GetCode(string secret)
@@ -61,7 +68,7 @@ namespace TwoStepsAuthenticator
 
         public bool CheckCode(string secret, string code)
         {
-            if (usedCodes.IsCodeUsed(secret, code))
+            if (usedCodes.Value.IsCodeUsed(secret, code))
                 return false;
 
             var baseTime = DateTime.Now;
@@ -70,7 +77,7 @@ namespace TwoStepsAuthenticator
                 var checkTime = baseTime.AddSeconds(30 * i);
                 if (GetCode(secret, checkTime) == code)
                 {
-                    usedCodes.AddCode(secret, code);
+                    usedCodes.Value.AddCode(secret, code);
                     return true;
                 }
             }
diff --git a/TwoStepsAuthenticator/UsedCodesManager.cs b/TwoStepsAuthenticator/UsedCodesManager.cs
index d60e1cb..3d4247b 100644
--- a/TwoStepsAuthenticator/UsedCodesManager.cs
+++ b/TwoStepsAuthenticator/UsedCodesManager.cs
@@ -41,14 +41,14 @@ namespace TwoStepsAuthenticator
         public UsedCodesManager()
         {
             codes = new Queue<UsedCode>();
-            cleaner = new Timer(TimeSpan.FromSeconds(5).TotalMilliseconds);
+            cleaner = new Timer(TimeSpan.FromMinutes(5).TotalMilliseconds);
             cleaner.Elapsed += cleaner_Elapsed;
             cleaner.Start();
         }
 
         void cleaner_Elapsed(object sender, ElapsedEventArgs e)
         {
-            var timeToClean = DateTime.Now.AddSeconds(-5);
+            var timeToClean = DateTime.Now.AddMinutes(-5);
             lock (codeLock)
             {
                 while (codes.Count > 0 && codes.Peek().UseDate < timeToClean)