Making a cipher

>>1116944
one time pad

>>1116954
>one time pad
Needs to be reusable.

People normally figure out ciphers by finding common letters like E and determining the words that way, what if I make different symbols for E depending on it's placement in words?

E.G. in "THE", E is the 3rd letter and in "BE" E is the 2nd.

How much harder will it be to figure out such a code?

>>1116944
use a unique 5 digit alphanumeric combination for each letter/number and space.

figure that shit out

>>1116959
Reusable often enough that you can't just make a really big one time pad and use a small part of it each time?

Does this have to be done manually so you can't computerize it? Does it only need to be strong against someone analyzing an intercepted code, or does it have to hold up against people who have many examples of decoded messages to compare to the encoded ones?

>>1116994
Just so whoever wants to can't just pick up a sheet of my notes and figure out the code by looking for "single-letter words" or repeated letters (like E).

And it has to be permanent so it can be memorized once.

>>1116989
Post read (only replying to let you know I considered it w/o replying)

>>1116944
For example you can take the numbers of the letters in the alphabet and use some formula to scramble them.

For example the word "hello", could be translated into (8)(5)(12)(12)(15), now you can use a mathematical formula to rearrange them, for example, you can multiply by the number of letters in the word and divide by the position the letter is in that word, creating a new word, although with the same number of letters.
To get the word back reverse the process, the more complex the formula is the harder it will be to decode.

Figure that shit out! Have some imagination

>>1116944
How secure do you want it to be? If you want it to be strong against actual codebreakers you're going to need to use something like AES - i.e. actual encryption.
On the other hand, if it's just for fun (and you don't mind it taking a while to encode/decode messages) you could use something along the lines of a book cipher:
https://en.wikipedia.org/wiki/Book_cipher

Anything you think up has probably been invented before. What you described sounds like a basic version of the Enigma machine.

>>1116944
just drink lots of ovaltine

>>1116944

Some more requirements would be nice.

How secure does it have to be?
What will be the IQ of the person encoding/decoding (approximate)?
Will the person encoding and decoding have access to a calculator?

If you're just fucking around, go ahead and use a rotating cypher it's not very hard to break but the average dude won't be able to read it.

If you're trying to sneak by any 3 letter agencies you'll need something much more sophisticated and the #1 rule of encryption is don't fuck with it unless you went to school for it.

>>1116944
There are two kinds of codes: the ones that will keep secrets from an annoying sibling, and the ones that will keep secrets from a determined government agency. If you're not famous, infamous, or involved in illegal/covert activities, no one is likely to care enough to break a substitution cipher like you described, which is an easy-to-use but weak method of encryption. An autokey cipher offers much better security while being easy to encode and decode by hand. Actually being secure, though, would take more complex systems or a one-time pad.