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May 29, 2013

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Have I come up with a new unknown unbreakable cipher meth...

While we're at it, how about examining my new cipher technique here: http://www.topix.c om/forum/science/c ryptography/T7E61P OFL75K4B8NQ My technique is designed not only to create as strong a cipher as possible, but to do it using as small and easily manageable a key as possible.  (May 31, 2013 | post #3)


Have I come up with a new unknown unbreakable cipher meth...

It's clever, but it largely defeats the purpose of using a cipher code in the first place. The whole idea of pencil-and-paper cryptography is that if you have a long message which you wish to keep secret and the text in which the message is written is too large to easily hide, you encrypt the text with some manner of cipher method, using a much shorter key to encrypt/decrypt the text. That way, instead of hiding an entire book or other large document from an adversary, you only have to hide a small slip of paper from the adversary, and it doesn't matter if they find the book or other document. To do what you are suggesting, you would need two cipher keys to encrypt a single document, and each cipher key would probably have to be significantly bigger than the encrypted text itself. This means that successfully hiding the cipher keys to keep the document secret would be even more difficult than simply writing the document in plaintext and then hiding the document. It does sound like a fairly secure cipher. However, it would probably be easier and just as effective to simply use a one-time-pad. If you wanted to make it even more secure, you could use a running key cipher, which is to say a cipher using an existing text such as a novel, as the cipher key, and then use a one-time-pad on top of it. That way, someone would still have a very difficult time decrypting the message unless they were to find both keys, and neither of the keys would have to be any longer than the original message itself. That would be easier to manage than the method which you have described, and probably even more secure. You see, on the one hand, a one-time-pad is utterly impossible to decrypt without the key, but the key is very large and difficult to hide. On the other hand, a running-key cipher is possible, albeit difficult, to decrypt without the key, but the key is relatively easy to keep secret, i.e. when the inquisitor comes to your house, accuses your of heresy, and inquires about that botanical encyclopedia you used as a running-key to encrypt secret messages to other heretics, you can tell him "Oh no Sir, it's not a cipher key. It's just an encyclopedia. " If you put a one-time-pad and a running key cipher together, it would certainly be easier to manage than the method which you described. I can't really imagine how someone would go about cracking your code without access to Text-B, the text containing the letters which are to be removed from Text-A in order to to produce the actual message. However, if Text-A was itself and intelligible text, such a a novel or encyclopedia, it would then be possible, and perhaps even very easy, for someone with access to Text-B to simply guess what Text-A was, simply by searching for texts containing most of the same letters as Text-B. For instance, if the message was "attackatdawn ", and Text-A was the US constitution, Text-B would probably read something like this: "WETHEPEOPLEO FTHEUNITEDST[AT]ES INORDERTOFORMAMORE PERFEC[T]UNIONEST[ A]BLISHJUSTI[C]EIN SUREDOMESTICTRANQU ILITY ..." and so on. Already, anyone could easily guess what Text-A was. On the other hand, if Text-A was not an intelligible document but was instead just a random series of letters and numbers, it would be very obvious to anyone who found it that it might be the cipher key, and because Text-A AND Text-B both have to be bigger than the original message, it would be even harder to keep them hidden than to simply hide the original message. Thus not only would a one-time-pad together with a running key cipher be much easier to manage, it would also be far more secure as well. I don't mean to bust your bubble. Honestly, it is a very clever idea, and I can't imagine how someone could possibly crack your code without access to Text-B, but I think your method is far too cumbersome to be practical and the method I just described, of using a one-time-pad together with a running key, would be much easier and more secure.  (May 31, 2013 | post #2)


Developing a new cipher technique

No, I didn't just re-invent the Vigenere cipher. Actually, I'm a fan of old-fashioned pencil-and-paper ciphers, and I've created a unique encipherment method consisting of multiple other methods, including a unique method of my own invention which I can't find any references to anywhere on the internet, layered on top of one another. I just wanted to describe how it worked, get some feedback, and see if anyone wanted to try and crack it just for fun. First, you decide what characters you want to be able to encrypt. I've chosen the following: ABCDEFGHIGKLMNOPQR STUVWXYZ [SPACE] ,.?!' Then, you decide how many cipher symbols you want the cipher text to have. I've chosen to use 100 distinct symbols, simply because they fit nicely on a 10x10 grid and because if I write the cipher text as a series of numbers in Arabic numerals, there are exactly 100 possible two-digit number combinations excluding negatives - 00, 01, 02, 03, and so on up to 99. Then, you calculate the relative frequencies, in the English language, of each of the plaintext characters you wish to be able to encrypt, and assign more cipher symbols to the characters which occur more frequently, and fewer to the characters which occur less frequently, to even out the letter frequency and impede letter frequency analysis. I've chosen the following number of symbols for each plaintext character: A: 7 B: 1 C: 1 D: 4 E: 10 F: 1 G: 1 H: 5 I: 6 J: 1 K: 1 L: 3 M: 1 N: 6 O: 6 P: 1 Q: 1 R: 5 S: 5 T: 7 U: 1 V: 1 W: 1 X: 1 Y: 1 Z: 1 [SPACE]: 16 ,: 1 .: 1 ?: 1 !: 1 ': 1 You can draw weird shapes, or just use various numbers, or whatever. This creates your unique cipher alphabet. Of course, you have to be careful not to use the same symbol more than once in this stage. Once you've done that, you create a grid of squares, with just enough squares so that there's one for each of your cipher symbols. I have chosen to use a simple 10x10 grid, because it has exactly enough room for the 100 characters which I use. Then, you number each square on the grid from left to right, top to bottom, starting from zero and counting up to however many squares there are. Then, you write each of your cipher symbols into a different one of those squares, in a completely random order. I refer to this as the "primary key". Then you create the "secondary key". The secondary key is actually a series of many smaller cipher keys, each the length of a different prime number. Basically, you create a short, two-character cipher key composed of two randomly chosen symbols from your cipher alphabet, and then a three character cipher key composed of three randomly chosen symbols from your cipher alphabet, and then a five character cipher key, and then a seven character cipher key, and so on up to however big of a prime number you wish to use. This collection of miniature keys strung together comprises the secondary key. The plaintext is then encrypted via the following steps: 1st - You take each plaintext character and you substitute it with the associate symbol from your cipher alphabet. 2nd - You take each symbol you have written down, and find its associated number in the grid in which you recorded the primary key. 3rd - You then do the same for all of the symbols in the secondary key. 4th - You then encipher the text with each of the mini-keys in the secondary key one after another, using each mini-key to encipher the text in the fashion of a Vigenere cipher. That is to say that you find the number, according to your primary key, of each symbol in the text; add to that number the associated number, according to your primary key, of the associated symbol in whatever mini-key in the secondary key you are currently on; find the symbol associated, according to your primary key, with the new number; and then substitute that symbol in place of the old one; continuing until you have reached the end or your secondary key. To decrypt the cipher text, you reverse the process.  (May 29, 2013 | post #1)