thanks for your answers. right it's about bitcoin puzzle 66 and 67.
as soon as the public key becomes visible in the mempool anyone can calculate the privkey within a few seconds and grab coins.
as far as i understand RBF is no solution for the mentioned problem. is there no other solution without submitting the transaction
to a miner pool- that wouldn't be an option either as lack of trust. so with mempool there is no hope and the privkey would be
compromisable,no other solution?