Xerox Corporation

Whitehawk Software LLC

Christian Peter Jacobi

Robert Thomas Krivacic

Christopher Angel Kantarjiev

Mark D Weiser

Alan J Demers

Ronald A Frederick

Engineers at a software maker can insert software markers, making a compiler provide object code markers that appear to invoke activities from the protection library, but actually have the effect of providing information to a protection process. The engineers can build a protected object file, from which a software protection tool can provide an executable file. The software protection tool can include any tool that can use a pointer to a program statement, including creating DLL's. Alternatively, the system can identify object code markers by their referencing known functions from CALL instructions. The software protection tool can reference and remove the CALL instructions at distinct build and protecting stages to differing degrees of interference with the program to be protected&#x2014;to test the program without any protection; to test some aspects of protection; to replace the CALL instructions to refer to strong protection functions that effectively make the program tamper proof; to provide information to debug protection.

Denoting precise locations and arguments in binary program code

As an electronic pen (16) moves across a display screen (12), a position resolver (14) generates a series of x,y-coordinate positions which are sent to a remote computer system (20) having a relatively high latency or time delay before the positions are processed and intended display information is returned to the memory cells of a memory array (24) which controls the display on the display screen (12). During the time delay, a temporary display of the trajectory is created, preferably in light gray or another distinguishable color. Each x,y-coordinate position is compared (32) with an immediately preceding coordinate position to determine whether the pen has moved. If so, the new coordinate is stored in a memory (36) which stores a preselected number of the most recent coordinate positions and to a toggle circuit (38) which toggles a preselected bit of the display information stored in the corresponding memory cell of the memory array. After a preselected time, determined by clocking the recent coordinate position memory (36), the oldest stored coordinate position is clocked out and display information in the memory cell corresponding to the clocked out coordinate position is retrieved (42) and analyzed (44). If the toggled bit is still in the toggled position, the toggle circuit (38) toggles it back to the initial state. If the preselected bit has been reset by the intended drawing in the interim, it is not altered.

Local inking with gray pixels

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Palo Alto, CA, United States of America

Christian Peter Jacobi