I know theres AES and PGP, but all electronics stuff still has backdoors. You can’t backdoor a piece of paper and a writing utensil.
Book cypher. 2 copies of the exact same book. The cypher is an agreed upon system of indicating letters or words.
No, not possible.
The closet we’ve seen are the zodiac killer’s scribbles and they lasted as long as they did because he made a mistake (and frankly because no security researcher was really trying).
Modern cryptography works because it shuffles data around so much that it appears random. There’s simply no way to do those sorts of operations with just pen and paper.
The code could associate skipped or unskipped symbols with the location of stars in the sky at a distant point in time unknown to those trying to break the code
Have a list of pregenerated numbers that each participant has, and do a ciphering system based on those. Like a book cipher, but smaller, more portable, and faster to eat in case of emergency.
Make your own language
Time to put my Chinese language skills to work?
English + Mandarin (Pinyin) + Cantonese (Jyutping) = ???
Canto-Mandar-lish? 🤔
Actually it might work. You’d need to understand 3 languages to decipher it.
Does the NSA/FSB/CCP have tri-lingual speakers? 🤔
Maybe I should learn some Navajo to add more fun to the mix? 😁
The Navajo did pretty well in WWII
Also maybe microdots would be more effective. Not exactly pen and paper, but still analog. Hard to crack a code you can’t find.
Yes it’s fairy simple, basically you draw random things and think about what you want to write about, then the person who needs to read it just go back in time and reads your mind from that period using your paper card. People do it all the time, it’s called Art. Go to museum and you find plenty of those.
Maybe something akin to a book code, although machine learning may be able to crack those by that time.
I am not a cryptographer so I have no idea really.