what to do with a question like these, OP is missing, the question is not clear,etc.

@kelalaka if the question is unclear and reasonable assumptions still don't allow to write an answer, then it should be closed as "unclear what you are asking"

(and you maybe have given the poster a few days to respond)

(which I've done just now for the above question)

@SEJPM ok, Thanks

@SEJPM thanks for the nice post on Massey-Omura protocol. Somewhere I remember that but couldn't. I tried but stuck.

@kelalaka I also only vaguely remembered that I had seen the protocol before, but luckily I also remembered where and thus could look it up and then wikipedia lead me to the security result :)