System.Data.SQLite

If you're on a domain controller this may or may not work depending on how the domain administrator has setup recovery keys for EFS files.  The actual syntax is very similar to compressing and decompressing files.  It is also completely transparent.  Once encrypted, the file can be opened normally by the user that encrypted it or an administrator.

using System;
using System.Data;
using System.Text;
using System.Data.Common;
using System.Data.SQLite;
 
namespace test
{
  class Program
  {
    static void Main(string[] args)
    {
      SQLiteConnection.EncryptFile("c:\\mydatabasefile.db3");
      SQLiteConnection.DecryptFile("c:\\mydatabasefile.db3");
    }
  }
}