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Basic formatting applied. Unnecessary comments have been removed. Suspicious code is covered by TODO.

Hcs.Client/GostXades/Helpers/ConvertHelper.cs

@@ -0,0 +1,12 @@
+using System.Numerics;
+
+namespace Hcs.GostXades.Helpers
+{
+    public static class ConvertHelper
+    {
+        public static string BigIntegerToHex(string str)
+        {
+            return BigInteger.Parse(str).ToString("X");
+        }
+    }
+}