Security * Spectrum * A. Thompson [Funny, the REM in the program calls him A Andrews...] Type-in the program in listing one and save it. Next, load the program you wish to protect with 'Security' and type-in the following commands: MERGE "Security" to merge 'Security' in with the program you wish to protect. Then type: GO TO 9900 You should get a listing of a line containing a number to be protected. The listing shows the text representation, or face value, which is not necessarily its real value. You will be shown the true value and be prompted for a new text representation. If you press ENTER the text representation will remain the same, or, if your input was of the same length as the text representation, it will be replaced by your input. If your input was not the length required, it will ask you again until it receives one of the correct length. When you have finished protecting your program, delete lines 9900 onwards. This program changes the text representation of a number in a listing, without changing its value, so that when the program is listed, it appears to be correct, but if you were to edit a line and then insert it back into the program, it would not work. It is especially useful for loader programs, e.g., the following program could be changed from: 10 CLEAR 24999: LOAD ""CODE: RANDOMIZE USR 25000 to: 10 CLEAR 12345: LOAD ""CODE: RANDOMIZE USR 99999 and it would work perfectly, so long as the line was not edited and replaced in the program.