So I was writing a "program" and I was wondering how could one make a kill-switch for it? Like if I would like to suddenly, for some reason, remove it and everything associated with it.

My first idea was to make the program connect to a server and request, lets say a text file. If text file contains 0 then it does nothing, if it contains 1 then the program wipes itself without a trace. But that would be a major problem for more than 1 user, because then all of the programs would be removed.

Second idea was to make it filter by the IP. When a program is ran, it would connect to the server and put it's IP. Then I could issue a kill-command to some text file, it checks if the IP matches and acts accordingly. But that would also be a major problem with LAN networks where there are more than 1 computer.

I got an idea writing this - what if the program upon execution would generate a unique key, write it somewhere safe, like deep in a registry and then connect to the server and put the IP and the unique key. So when I would like to kill a specific program, I would just issue the unique key for it... but I guess it would be a problem with PC's without internet. Then maybe a timer...?

lolz, I probably answered my own question with the last idea
But I'd like to hear other thoughts anyway.

You should specify exactly how you'd like to "kill" it(on your end, not user).

If is *program unknown to user* then shouldn't you have access to that piece of code *somehow*, could make an option to del it.

The way I'd modify your solution is:

client: program starts, connect to server.
client: sends info about its system such as hostname[for your sake] and a "unique" identifier.
server: if doesn't exist log; check a list/db to see if lives/dies, send appropriate instructions.

Unique identifier could be ComputerSystemProduct UUID, in powershell:

PS K:\>(Get-WmiObject Win32_ComputerSystemProduct).UUID
XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX

You can find several other UUIDs on a windows system, or something like a MAC address could also work.

Then maybe a timer...?

If you only need it to run a certain amount of time, then you could delete on a specific date/time.. or an amount of time after first run.

Could always hop on the BotNet band wagon and issue commands via an IRC channel.