[#1] Define SDK structure

TODO: Вынести маппинг модель -> grpc в отдельный слой

Signed-off-by: Ivan Pchelintsev <i.pchelintsev@yadro.com>

sdk/src/FrostFS.SDK.Cryptography/Tz/Helper.cs

@@ -0,0 +1,30 @@
+using System.Security.Cryptography;
+
+namespace FrostFS.SDK.Cryptography.Tz
+{
+    public static class Helper
+    {
+        public static ulong NextUlong(this RandomNumberGenerator rng)
+        {
+            var buff = new byte[8];
+            rng.GetBytes(buff);
+            return BitConverter.ToUInt64(buff, 0);
+        }
+
+        public static int GetLeadingZeros(ulong value)
+        {
+            var i = 64;
+            while (value != 0)
+            {
+                value >>= 1;
+                i--;
+            }
+            return i;
+        }
+
+        public static int GetNonZeroLength(this ulong value)
+        {
+            return 64 - GetLeadingZeros(value);
+        }
+    }
+}