Konnichiwa!

Have you ever wanted to be able to write something down, or send someone a secret message, without anyone else besides you or your friends being able to read it?

Or perhaps you are simply looking for a way to come up with a more secure, yet easy to remember password for something?
(Like your Paint account.)

Well, the techniques in these lessons can be used for these, and for many other things, as well.

The techniques in these lessons all use a single, simple idea: The idea of treating letters and other characters as numbers.

I first became familiar with this idea when helping my dad do a quest in a certain RPG, which used an enciphering technique called "One-time pad", which assigns a numeric value to each letter of the alphabet, with "A" being 0, "B" being 1, "C" being 2, etc., all the way up to "Z", which is 25.

Let's say your message is:

"......Souzouryoku ga Tarinaiyo -Denshousha Higana"
(That's a slightly modified version of my signature in romaji, BTW.)

Well, One-time pad essentially allows you to "password protect" your Message, by enciphering it.

For example, let's say you use the word "Shark" as your "password".

"S" is the first letter of the message, and being the 19th letter of the alphabet, has a value of 18, and "S" is also the first letter of the cipher in this case, so you simply add 18+18=36.

Now, since the last letter of the alphabet only has a value of 25, any time the result exceeds that, you subtract 26, in this case, 36-26=10, which would be "K", the 11th letter of the alphabet.

You keep adding the cipher/password to the message like this, adding the value of each letter of the cipher to each letter of the message (O+H=V, U+A=U, etc.,) until you've reached the last letter of the cipher (in this case, the "K" in "Shark", and then you start at the beginning of the cipher again, as many times as necessary, until the entire message is enciphered.

The result should be this:

"......Kvuqymyyfum na Kkjpnrsqv -Dvxkoolczh Hzqsua"
(Hopefully I did that right, lol!)

Now this is a great idea, but it doesn't take into account a variety of different things, including spacing, capitalization, non-letter characters, etc., which means it's not the most effective way of concealing a message.

There are a number of ways you can make it better, however, such as using better ciphers (rather than a 5 letter word like "Shark", enciphering the same message multiple times, and even enciphering things in reverse, by subtracting the value of each cipher Letter from the message, rather than adding it.

To decipher the message, you do just that: subtract the value of the cipher from the enciphered message, and whenever the result is negative, you simply add 26 to it, just like when it exceeds 25 when adding it.

You can also encipher the message this way, however, and if enciphering the same message multiple times, could apply some ciphers using addition, and some using subtraction, making it more secure.
(And to decipher a message enciphered in reverse, you use addition, of course.)

How can this help you come up with better passwords?

It's simple: Combine multiple passwords together using this technique.

The result will look essentially like a bunch of random letters, yet you can remember it in a pinch if necessary, by going through the same process used to create it.
(You need to be very careful not to make any mistakes when calculating it and entering it for the first time, though.)

Anyway, that's all for this lesson.

In the next one, I'll share an enciphering technique I came up with, that uses the same basic principles as One-time pad, but adds additional characters into the mix, making it WAY more secure.

Sayonara!