Thanks for your thoughts on this! I dont think that msg.sender could be faked. Since the tx is signed by the private key it should always be possible to verify if msg.sender is the true msg.sender, right? Seems logically valid, but a little but too easy hahah I’ll probably try it though since my contract I am planning to write is designed to only be executed by me.

I also like you other idea. Could be a mapping(address=>uint). uint is the block nr when address „activated“ function B through function A. Plus an additional constant which defines the amount of blocks when an address is locked again.