From 7afa9a729114333fa400567bc35332882a212787 Mon Sep 17 00:00:00 2001
From: Dmitry Dzygin <dmitriy.dzygin@gmail.com>
Date: Thu, 1 Mar 2018 14:28:41 +0100
Subject: [PATCH] Captcha code refactoring

---
 .../WebClient/Captcha/CaptchaConfiguration.cs | 75 +++++++++----------
 .../Core/WebClient/Captcha/Encryption.cs      | 23 ++++--
 2 files changed, 52 insertions(+), 46 deletions(-)

diff --git a/Composite/Core/WebClient/Captcha/CaptchaConfiguration.cs b/Composite/Core/WebClient/Captcha/CaptchaConfiguration.cs
index ac630c9367..6bdf07258b 100644
--- a/Composite/Core/WebClient/Captcha/CaptchaConfiguration.cs
+++ b/Composite/Core/WebClient/Captcha/CaptchaConfiguration.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.IO;
 using System.Xml;
 using Composite.Core.Extensions;
@@ -9,59 +9,54 @@ namespace Composite.Core.WebClient.Captcha
     internal static class CaptchaConfiguration
     {
         private static readonly string CaptchaConfigurationFilePath = @"App_Data\Composite\Configuration\Captcha.xml";
-        private static readonly object _syncRoot = new object();
 
-        private static string _password;
+        public static string Password { get; }
 
-        public static string Password
+        static CaptchaConfiguration()
         {
-            get
-            {
-                if (_password != null) return _password;
-
-                lock (_syncRoot)
-                {
-                    if (_password != null) return _password;
+            string configurationFilePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, CaptchaConfigurationFilePath);
 
-                    string configurationFilePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, CaptchaConfigurationFilePath);
+            string password = null;
 
-                    if (C1File.Exists(configurationFilePath))
+            if (C1File.Exists(configurationFilePath))
+            {
+                var doc = new XmlDocument();
+                try
+                {
+                    using (var sr = new C1StreamReader(configurationFilePath))
                     {
-                        var doc = new XmlDocument();
-                        try
-                        {
-                            using (var sr = new C1StreamReader(configurationFilePath))
-                            {
-                                doc.Load(sr);
-                            }
+                        doc.Load(sr);
+                    }
 
-                            var passwordNode = doc.SelectSingleNode("captcha/password");
-                            if (passwordNode != null && !string.IsNullOrEmpty(passwordNode.InnerText))
-                            {
-                                _password = passwordNode.InnerText;
-                            }
-                        }
-                        catch (Exception)
-                        {
-                            // Do nothing
-                        }
+                    var passwordNode = doc.SelectSingleNode("captcha/password");
+                    if (!string.IsNullOrEmpty(passwordNode?.InnerText))
+                    {
+                        password = passwordNode.InnerText;
+                    }
+                }
+                catch (Exception)
+                {
+                    // Do nothing
+                }
 
-                        if (_password != null) return _password;
+                if (password != null)
+                {
+                    Password = password;
+                    return;
+                }
 
-                        // Deleting configuration file
-                        C1File.Delete(configurationFilePath);
-                    }
+                // Deleting configuration file
+                C1File.Delete(configurationFilePath);
+            }
 
 
-                    _password = Guid.NewGuid().ToString();
+            password = Guid.NewGuid().ToString();
 
-                    string configFile = @"<captcha> <password>{0}</password> </captcha>".FormatWith(_password);
+            string configFile = @"<captcha> <password>{0}</password> </captcha>".FormatWith(password);
 
-                    C1File.WriteAllText(configurationFilePath, configFile);
+            C1File.WriteAllText(configurationFilePath, configFile);
 
-                    return _password;
-                }
-            }
+            Password = password;
         }
     }
 }
diff --git a/Composite/Core/WebClient/Captcha/Encryption.cs b/Composite/Core/WebClient/Captcha/Encryption.cs
index dc0eded538..74b7c37748 100644
--- a/Composite/Core/WebClient/Captcha/Encryption.cs
+++ b/Composite/Core/WebClient/Captcha/Encryption.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Globalization;
 using System.IO;
 using System.Security.Cryptography;
@@ -16,19 +16,25 @@ internal static class Encryption
 
         static Encryption()
         {
-            var md5 = MD5.Create();
-
             string key = Environment.MachineName + CaptchaConfiguration.Password + HostingEnvironment.ApplicationPhysicalPath;
 
             byte[] keyBytes = Encoding.UTF8.GetBytes(key);
 
-            _encryptionKey = md5.ComputeHash(keyBytes);
+            using (var hashAlgorithm = MD5.Create())
+            {
+                _encryptionKey = hashAlgorithm.ComputeHash(keyBytes);
+            }
         }
 
         public static string Encrypt(string value)
         {
             Verify.ArgumentNotNullOrEmpty(value, nameof(value));
 
+            return ByteToHexString(RijndaelEncrypt(value));
+        }
+
+        private static byte[] RijndaelEncrypt(string value)
+        {
             // Create a RijndaelManaged object
             // with the specified key and IV.
             using (var rima = new RijndaelManaged())
@@ -49,7 +55,7 @@ public static string Encrypt(string value)
                         swEncrypt.Write(value);
                     }
                     // Return the encrypted bytes from the memory stream.
-                    return ByteToHexString(msEncrypt.ToArray());
+                    return msEncrypt.ToArray();
                 }
             }
         }
@@ -59,6 +65,11 @@ public static string Decrypt(string encryptedValue)
             Verify.ArgumentNotNullOrEmpty(encryptedValue, nameof(encryptedValue));
             byte[] encodedSequence = HexStringToByteArray(encryptedValue);
 
+            return RijndaelDecrypt(encodedSequence);
+        }
+
+        private static string RijndaelDecrypt(byte[] bytes)
+        {
             using (var rima = new RijndaelManaged())
             {
                 rima.Key = _encryptionKey;
@@ -68,7 +79,7 @@ public static string Decrypt(string encryptedValue)
                 ICryptoTransform decryptor = rima.CreateDecryptor();
 
                 // Create the streams used for decryption.
-                using (var msDecrypt = new MemoryStream(encodedSequence))
+                using (var msDecrypt = new MemoryStream(bytes))
                 using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                 using (var srDecrypt = new C1StreamReader(csDecrypt))
                 {