This is how all modern cryptography works. A deterministic cipher is functionally no different from pig Latin when it comes to actual security. An electronic solution like public key cryptography is infinitely more secure. If you’re especially paranoid you can generate the cryptotext locally and send it by email; that would be much safer than anything you could achieve by hand.

It sounds like you ruined it for yourself. Judging from all of your replies and especially this one in particular, you seem to lack the ability to take basic accountability for your own actions. I would suggest reflecting on the cause-and-effect in the anecdotes you’ve shared and try to visualize how they might played out were the roles reversed and other people spoke to/treated you the way that you describe treating them. Even if you have some degree of sociopathy (I’m not a mental health professional by any means), you should still be able to reflect on these situations on an intellectual and objective level and consider that you might be the cause of these conflicts.