摘要 |
The invention relates to a method and a device for the tap-proof and manipulation-proof transmission of messages between a server and the computer of a client, over a computer network, and for the decoding of encoded messages by clients. The method and the device can be especially used for encoding online accounts, especially for online banking. The device, described as a cryptocard, is preferably a flat appliance comprising photosensory elements on the rear side and a display on the front side. The device also contains a logic element/processor and an electronic memory containing codes. It is placed on the screen of the computer of the client, on which the following is displayed in image format: (1) an encoded message, (2) the number of the code required for the decoding, and (3) the co-ordinates of the actual position of the indicator symbol. This information received by the photosensors is decoded by the logic element/processor by means of the code, and the message is decoded and displayed in a clearly visible manner on the display. The indicator symbol on the screen is simulated on the display. By clicking buttons marked with characters on the cryptocard, a message can be transmitted from the client to the server. As the marking of the buttons by the characters is fixed previously at random by the server and transmitted in a tap-proof manner to the cryptocard, the transmission of the message from the client to the server is also tap-proof. The tap-proofness in both directions allows a protocol for online banking to be implemented, which renders the PIN tap-proof and prevents the falsification of transfers. |