Technical Characteristic 1. Typical Whiteboard is based on non real time method which transmits data via mail or Facebook after writing finished. However, our invention provides technique which makes data sharing and modifying in real time. 2. The efficiency of communication bandwidth usage is high because pixels changed are only transmitted on screen. 3. Extra hardware device is not needed because this invention can be implemented by software. Practical Use and Advantage 1. Providing real time messenger by hand writing on mobile devices 2. Tutoring in private for subjects such as math and science including figures and graphs. 3. Information exchange in remote for design engineers. 4. Compatible use between hetero devices such as Windows, Android, and iOS. 5. Convenient extension and modification of functions by software upgrade 6. Supporting video and audio simultaneously with whiteboard