Auth System

FoodsharingSiegen.Server/Auth/AuthHelper.cs

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+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.IdentityModel.Tokens;
+
+namespace FoodsharingSiegen.Server.Auth
+{
+    /// <summary>
+    /// The auth helper class (a. beging, 04.04.2022)
+    /// </summary>
+    public static class AuthHelper
+    {
+        #region Public Method Decrypt
+
+        /// <summary>
+        /// Decrypts the crypted text (a. beging, 04.04.2022)
+        /// </summary>
+        /// <param name="cryptedText">The crypted text</param>
+        /// <returns>The string</returns>
+        public static string Decrypt(string cryptedText)
+        {
+            CreateAlgorithm(out var tripleDes);
+            
+            var toEncryptArray = Convert.FromBase64String(cryptedText);
+
+            
+
+            var cTransform = tripleDes.CreateDecryptor();
+            var resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
+
+            tripleDes.Clear();
+
+            return Encoding.UTF8.GetString(resultArray);
+        }
+
+        #endregion
+
+        #region Public Method Encrypt
+
+        /// <summary>
+        /// Encrypts the plain text (a. beging, 04.04.2022)
+        /// </summary>
+        /// <param name="plainText">The plain text</param>
+        /// <returns>The string</returns>
+        public static string Encrypt(string plainText)
+        {
+            CreateAlgorithm(out var tripleDes);
+            
+            var toEncryptArray = Encoding.UTF8.GetBytes(plainText );
+            
+            
+ 
+            var cTransform = tripleDes.CreateEncryptor();
+
+            var resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
+
+            tripleDes.Clear();
+
+            return Convert.ToBase64String(resultArray, 0, resultArray.Length);
+        }
+
+        #endregion
+
+        #region Public Method GetSigningKey
+
+        /// <summary>
+        /// Gets the signing key (a. beging, 04.04.2022)
+        /// </summary>
+        /// <returns>The security key</returns>
+        public static SecurityKey GetSigningKey() => new SymmetricSecurityKey(Encoding.ASCII.GetBytes(SigningKey));
+
+        #endregion
+
+        #region Public Method ValidateToken
+
+        /// <summary>
+        /// Validates the token using the specified token (a. beging, 04.04.2022)
+        /// </summary>
+        /// <param name="token">The token</param>
+        /// <returns>A task containing the bool</returns>
+        public static async Task<bool> ValidateToken(string? token)
+        {
+            try
+            {
+                var tokenHandler = new JwtSecurityTokenHandler();
+                var result = await tokenHandler.ValidateTokenAsync(token, new TokenValidationParameters
+                {
+                    ValidateIssuerSigningKey = true,
+                    IssuerSigningKey = GetSigningKey(),
+
+                    ValidateAudience = true,
+                    ValidAudience = "FS-Siegen",
+
+                    ValidateIssuer = true,
+                    ValidIssuer = "FS-Siegen"
+                });
+
+                return result.IsValid;
+            }
+            catch (Exception e)
+            {
+                return false;
+            }
+        }
+
+        #endregion
+
+        #region Private Method CreateAlgorithm
+
+        /// <summary>
+        /// Creates the algorithm using the specified triple des (a. beging, 04.04.2022)
+        /// </summary>
+        /// <param name="tripleDes">The triple des</param>
+        private static void CreateAlgorithm(out TripleDES tripleDes)
+        {
+            var md5 = MD5.Create();
+            var keyArray = md5.ComputeHash(Encoding.UTF8.GetBytes(SigningKey));
+            md5.Clear();
+            
+            tripleDes = TripleDES.Create();
+            tripleDes.Key = keyArray;
+            tripleDes.Mode = CipherMode.ECB;
+            tripleDes.Padding = PaddingMode.PKCS7;
+        }
+
+        #endregion
+
+        /// <summary>
+        /// The signing key
+        /// </summary>
+        public const string SigningKey = "2uasw2§$%1nd47n9s43&%Zs3529s23&/%AW";
+    }
+}