init

Kreta.WebApi/Ellenorzo/Kreta.Ellenorzo.BL/VN/Logic/ApiSecurityLogic.cs

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+using System;
+using System.Linq;
+using Kreta.Core.Enum;
+using Kreta.Core.Exceptions;
+using Kreta.Ellenorzo.Domain.VN.Common;
+
+namespace Kreta.Ellenorzo.BL.VN.Logic
+{
+    /// <summary>
+    /// Author: Madách Ferenc, Kovács Kornél (DevKornél), Érsek Zalán Created On: 2019.11.
+    /// </summary>
+    internal class ApiSecurityLogic
+    {
+        private readonly ApiSecurity _apiSecurity;
+        public int ApiSecurityVersion { get; private set; }
+        public bool IsJogosult { get; private set; } = false;
+
+        private const int BitParityPosition1 = 6;
+        private const int BitParityPosition2 = 54;
+
+        private const int SumOfRandomNumbersMinimum = 7;
+        private const int SumOfRandomNumbersMaximum = 38;
+
+        public ApiSecurityLogic(ApiSecurity apiSecurity)
+        {
+            _apiSecurity = apiSecurity;
+            if (_apiSecurity == null) ///Security disabled from config
+            {
+                IsJogosult = true;
+                return;
+            }
+
+            ApiSecurityVersion = int.Parse(_apiSecurity.SecurityKey.Substring(33, 3));///#7
+        }
+        internal void ThrowExceptionIfNotJogosult()
+        {
+            if (IsJogosult)
+            {
+                return;
+            }
+
+            if (_apiSecurity.SecurityKey != null && ApiSecurityVersion == 1)
+            {
+                IsJogosult = ApiSecurityValidate();
+            }
+
+            if (!IsJogosult)
+            {
+                throw new BlException(BlExceptionType.NincsJogosultsag);
+            }
+        }
+
+        private bool ApiSecurityValidate()
+        {
+            return _apiSecurity.SecurityKey.Length >= 150 &&
+                _apiSecurity.SecurityKey.Length <= 200 &&
+                IsBitParityValid() && ///#3
+                ContainsSignatureLastChars() && //#6
+                ValidateRandomNumbersSum() && ///#4
+                ValidateSignature() && ///#5
+                IsNoiseAlphaNumeric(); ///#9
+        }
+
+        private bool IsBitParityValid()
+        {
+            bool IsBinary(char c) => c == '0' || c == '1';
+
+            return IsBinary(_apiSecurity.SecurityKey[BitParityPosition1]) &&
+                IsBinary(_apiSecurity.SecurityKey[BitParityPosition2]) &&
+                _apiSecurity.SecurityKey[BitParityPosition1] != _apiSecurity.SecurityKey[BitParityPosition2];
+        }
+
+        private bool ValidateRandomNumbersSum()
+        {
+            int sumOfRandomNumbers = int.Parse(_apiSecurity.SecurityKey[8].ToString());
+            sumOfRandomNumbers += int.Parse(_apiSecurity.SecurityKey[30].ToString());
+            sumOfRandomNumbers += int.Parse(_apiSecurity.SecurityKey[36].ToString());
+            sumOfRandomNumbers += int.Parse(_apiSecurity.SecurityKey[43].ToString());
+            sumOfRandomNumbers += int.Parse(_apiSecurity.SecurityKey[49].ToString());
+
+            return sumOfRandomNumbers >= SumOfRandomNumbersMinimum && sumOfRandomNumbers <= SumOfRandomNumbersMaximum;
+        }
+
+        private bool ValidateSignature()
+        {
+            var secretChars = _apiSecurity.SecurityKey.ToCharArray();
+
+            /// #5-1
+            int step5_1_AsciiValue = _apiSecurity.SecurityKey[28];
+
+            int countRandomChar = _apiSecurity.Signature.ToCharArray().Count(s => s == _apiSecurity.SecurityKey[28]); ///#5-2
+            int constValue = 7234599;
+
+            int sumValue = countRandomChar + step5_1_AsciiValue + constValue;
+            string binaryRepresentation = Convert.ToString(sumValue, 2); ///#5-3
+
+            var arraySize = binaryRepresentation.Length;
+
+            for (int i = 0; i < 31; i++)
+            {
+                secretChars[90 - i] = i < arraySize ? binaryRepresentation[arraySize - i - 1] : '0';
+            }
+
+            ///#5-4
+            int offset = int.Parse(secretChars[8].ToString());
+            var startBitPosition = 59;
+
+            void SwapPositions(int xIndex, int yIndex)
+            {
+                (secretChars[xIndex], secretChars[yIndex]) = (secretChars[yIndex], secretChars[xIndex]);
+            }
+
+            SwapPositions(startBitPosition + offset, startBitPosition + 31);
+            SwapPositions(startBitPosition + 10 + int.Parse(secretChars[30].ToString()), startBitPosition + offset);
+            SwapPositions(startBitPosition + int.Parse(secretChars[43].ToString()), startBitPosition + 17 + int.Parse(secretChars[49].ToString()));
+            SwapPositions(startBitPosition + int.Parse(secretChars[49].ToString()), startBitPosition + 30 - int.Parse(secretChars[49].ToString()));
+
+            var generatedSecretKey = new string(secretChars).Substring(startBitPosition, 32);
+            return _apiSecurity.SecurityKey.Substring(startBitPosition, 32) == generatedSecretKey;
+        }
+
+        public bool ContainsSignatureLastChars()
+        {
+            return _apiSecurity.SecurityKey.Substring(99, 3) == _apiSecurity.Signature.Substring(_apiSecurity.Signature.Length - 3, 3);
+        }
+
+        public bool IsNoiseAlphaNumeric() ///#9
+        {
+            int[] expectedNoisePositions = new int[6] { 42, 45, 94, 105, 114, 126 };
+
+            foreach (int i in expectedNoisePositions)
+            {
+                if (!char.IsLetterOrDigit(_apiSecurity.SecurityKey[i]))
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+    }
+}