Those unchanged pixels won't be transmitted. Only the changed part of the screen needs to be sent to the client. For example, RFB[RFC 6143] would send a 16-byte

Those unchanged pixels won't be transmitted. Only the changed part of the screen needs to be sent to the client. For example, RFB[RFC 6143] would send a 16-byte header with the size and position of a rectangular area of the screen followed by the pixels in that rectangle. Or multiple rectangles can be sent in one update message. But if you consider the case of text being typed, there will be a single rectangle per keystroke(s). Now I wonder if a sequence of these rectangles, all the same size and in roughly the same area of the screen, would lend to some sort of statistical analysis. At the very least the timestamps of the updates would tell you how fast the operator is typing. [RFC 6143] https://tools.ietf.org/html/rfc6143 https://tools.ietf.org/html/rfc6143