refactored data storage to use cipher table. added history table and insert triggers.

src/Core/Utilities/CoreHelpers.cs

@@ -0,0 +1,40 @@
+using System;
+
+namespace Bit.Core.Utilities
+{
+    public static class CoreHelpers
+    {
+        private static readonly long _baseDateTicks = new DateTime(1900, 1, 1).Ticks;
+
+        /// <summary>
+        /// Generate sequential Guid for Sql Server.
+        /// ref: https://github.com/nhibernate/nhibernate-core/blob/master/src/NHibernate/Id/GuidCombGenerator.cs
+        /// </summary>
+        /// <returns>A comb Guid.</returns>
+        public static Guid GenerateComb()
+        {
+            var guidArray = Guid.NewGuid().ToByteArray();
+
+            var now = DateTime.UtcNow;
+
+            // Get the days and milliseconds which will be used to build the byte string 
+            var days = new TimeSpan(now.Ticks - _baseDateTicks);
+            var msecs = now.TimeOfDay;
+
+            // Convert to a byte array 
+            // Note that SQL Server is accurate to 1/300th of a millisecond so we divide by 3.333333 
+            var daysArray = BitConverter.GetBytes(days.Days);
+            var msecsArray = BitConverter.GetBytes((long)(msecs.TotalMilliseconds / 3.333333));
+
+            // Reverse the bytes to match SQL Servers ordering 
+            Array.Reverse(daysArray);
+            Array.Reverse(msecsArray);
+
+            // Copy the bytes into the guid 
+            Array.Copy(daysArray, daysArray.Length - 2, guidArray, guidArray.Length - 6, 2);
+            Array.Copy(msecsArray, msecsArray.Length - 4, guidArray, guidArray.Length - 4, 4);
+
+            return new Guid(guidArray);
+        }
+    }
+}