I need to send a complex password to my machine. The machine needs to decrypt it and run it. I have not found enough resources for such an operation.
More detailed description:
I am developing a new feature for my 3D printer which runs on Repetier. (It may be on a different firmware that I can do this job). I want to change my 3D printer so it can understand special encrypted G-codes alongside normal g-codes. Lets describe it with an example:
Normally, 3D printers can read and apply standard g-code files like:
G28 G0 X10 Y20 E30 . . . etc. But I am developing a g-code encryption method which encrypts any g-code and turns it into a text like:
M999 !4#^ M999 ^s+.&&/..* …. . . etc. I want to change the firmware for my printer so it understands if the related g-code is encrypted by checking every line if it stars with M999 (or starts with some other pattern character which I will decide later).
To do is, I need to understand how Repetier works, especially how command debug works and how I can parse my encrypted code from my encrypted g-code file.
I could not understand how repetier.h / command.cpp works and how it parses the line and redirects to functional cases.
1 Answer
Looking through the source I found Commands.cpp that has a loop.
void Commands::commandLoop() { while(true) { ... Commands::executeGCode(code); } } If we find the executeGCode method, we see that it calls:
processMCode(com); And finding the processMCode method, we have the switch case you can add your own logic to.
void Commands::processMCode(GCode *com) { switch( com->M ) { case 3: // Spindle/laser on ... case 999: // Your custom logic After decoding your encrypted string, I think it would be best to call back into the first method mentioned, and let the process start from the top with the unencrypted command.
case 999: // Custom logic executeGCode(unencrypted); break;