Paper & Pencil Cryptography

[@hindustanspecials]

Last claps are mine. Thank you, professor. Accept my love from India♥

[@pyotrleflegin7255]

That, sir, was quite brilliant! Thank you for your insight.

[@GideonTheTeacher]

you are welcome. Used it successfully many times. including reminding myself of various codes written in my noteboods. Told it to ordinary Chinese on my trip there and they were so happy and told me how for them it is of special value...

[@noname-bu1ux]

Thank you. You're a fantastic instructor.

[@New2chem]

I have a question. What if you assign 2 numbers for every letter in the Alphabet. When sending a message like "A" would be 34 so it could be 1231. The person or persons would have the same Alphabet with the same numbers an that could be any 2 numbers would that be a way to send a text securely. I got the idea from OTP using rows of 5 digits.

[@GideonTheTeacher]

Yes, any plaintext that can be properly written as a series of digits can be so treated. I have given my students as an exercise to code an application of this pen and pencil method. And by the way it also works by spreading each digits to three, especially if you only mind the last digit. So 3 can be written 481 which sums to 13, you ignore the 1 so 481 ciphertext becomes 3 plaintext. the power of this method is the obscurity of the method itself. people in prison or otherwise without access to computers have used this successfully. Some of these stories are still confidential today.

[@ashokdewan6207]

I liked very much this paper & pencil method.

[@Shahada2012]

Thankyou.