/wrol/ - Without rule of law, or shtf.

Firstly, lets start with an easy to do cipher.

We all know the Polybius square right? If not, Polybius was this chillaxin and decided that he needed a new way to change letters to numbers. So why not just do the XY coordinates of letters? This is similar to the shit you learned in school, X coordinate = going horizontal Y coordinate is going down though. With an expansion of the square from 5x5 to 6x6 we now have 36 spaces, the whole Latin alphabet and numbers too. If we used the numbers only, it would still be the equivalent of a Caesar Cipher. So now we add the randomness of dice to the equation. In this example I assume you had written out a pad of dice rolls.

This is modular math though. Think of it like a clock. We generally don't say 13 o'clock. We say 1 o'clock. The clock is modular 12. So lets do this with 6. 5 + 3 is 2 not 8. If it helps, just subtract 6 until it becomes second nature.

>>909

This is an example of how you don't always need a random key, it just need to be random enough.

The CIA needed a way to get communications material to agents in the field. Using a One Way Voice Link (Numbers station). E05 Known as Cynthia transmitted groups in a 4 number format just like this. I also have confirmation from reading that this is the exact same system used. Anyways, a one time pad is pretty much a smoking gun for espionage, so CIA got the idea to give people books and use a system just like this. While the header is different, this works for us.

Firstly, both sides of the conversation need the same book. The page 67 for example is now said and written as 067. Secondly the amount of key text used is also transmitted, no less than 100 no more than what is on the page. I used 150 characters so the header will be 067/150

Step two write out the key and plain text. Notice at the top of the text I have written out 1,2,3 etc on top of each column. Those will transpose the book text to make a random looking text. This will now be used as the key for this message.

Step 3 write message on top and use math.

step 4 transmit the groups.

The to decrypt, subtract the key from the message and profit.

>>910

So far we've learned about one time pads and pseudo random sources of entropy as "additives", something you add to the plain text. But lets take this a step further. Now, we're going to go over something called serration. I don't know who the jack ass was who coined the term but its even used in the DoppelKastenSchlussel paper on the NSA website. So the term's been a round for a while.

This is a basic transposition… kinda. It breaks up the ciphertext, so when the analyst goes to analyze it, he finds the a frequency distribution for ciphertext binomes if they were scrambled.

So lets apply this to the playfair cipher. In this example we will use a serration of 20 digits to keep it simple, but cryptanalysts like me will check for multiples of 4 and 5 in serration if we believe it is being used. 21, is semi prime of 3 and 7 is long enough and obtuse enough to provide a lot of security. Mixing the serration of the DoppelKastenSchlussel with the keying of a book like the Australians did for coast watching and we get this hot mess of a medium grade cipher.

On top of this, we will key the square. This means we will use a shared secret with our intended target. This may be a word, phrase, or something else used to further secure the cipher.

Firstly we will draw are polybius square. But instead of the normal alphabet lets use the key "8chan". Remember to not write any of the key letters twice, otherwise you have to do a lot of erasing.

Like the CIA book cipher we will choose a page, a set amount of keying material and then write it in the key box. I chose 100 characters from page 157.

Now, write your message out, in the serration length you have chosen, In this example we will use 20 because its square and I can tell if I fuck up. Next we will write the keying material above or below it, I prefer to write the key first then the message.

Next we begin cryptographic operations. For the playfair which you might remember from school if not here is the run down.

If the letters are in the same row, such as 8 and c, shift one letter to the right. Since 8 is the first letter it is C, the letter the right of C is H. So X and 2 are Y and 3. 2 and 3 is 3 and X. If it goes off the edge of the square, just wrap around.

Cipher text digits on the same column? Just go down one spot. 8D is DK, C5 is EC, I2 is P9… get it?

Plain text and Key letter are the same? Just ignore it. Sometimes a cipher digit needs to encrypt to itself. If it doesn't I can slide a word over the cipher text and compare looking for collisions on letters. This was part of the downfall to the Enigma. This is also a problem with original playfair.

Not only do we have a key space for the polybius square but we also have the key material from the book and the crypto operation. This is much stronger than the CIA book cipher but still not as strong as the Dice and Polybius square. True random trumps pseudorandom any day.

Ciphertext fit neither situation? Cool. It forms a rectangle if you think about it. IS makes a rectangle with E and V as the other corner markers. Not making sense? Say that you have 8 and 0 as the digits needing to be encrypted, on the other corners it will be B and 4. It should make sense now.

Against normal people, this is high grade, against an adversary such as a dedicated sigint group, this will provide some buffer space until they try a the correct serration distance and a hill climb attack with computers.

lazy asshat is back with the maths

Firstly lets start with Decimal Fibinocci

54608 ← my seed

Now, look at the numbers under it, see where it says 9 and 0?

5+4=9

6+4=0

54608

9068

Now to add the next last digit and the first one on the second row, 8 and 9.

8+9=7 (mod10)

54608←seed

90687←generated bits

96456

Division

3/59 = 0.0508 47458

You can mix, this with the original decimal fib, you can also expand upon the 5 digit version to this and then double your key material generated for just some addition and calculator button presses with no deterministic source.

Middle halves

The only thing you have to do with this one is multiply the center and left side.

On the bottom of the image, we can see where we can use different patterns for keying substitution boxes. Some can be written diagonally. Some are circular, some are written top to down, etc.

Keyword keying

You've seen my original one where we take the keyword and type in the rest in the substitution box. But now, we can use the keyword as a transposition key based on the alphabet value. Otherwise, just go from left to right order.

So lets start with something basic, ADFGVX. This cipher works great because the letters are very distinct in morse code, not to mention the limited letters makes it harder to cryptanalyze. 6 letters, transposed over an odd transposition makes it much harder to crypt analyze.

Firstly, you will require a minimum of 10 letters for a password/phrase and a date/5 digit number.

My password is Roughnecks and my date is 7/4/1776

We will serialize the letters in the password. The letter that comes first in the alphabet is going to be number 1, the next is 2 and so on. So C is one, there is no D, but there is an E so E is 2, G is 3 and so on, 0 is the final letter.

Once you have serialized the key, underneath, go to the date you've written down, make sure you have 5 numbers out of it. Make up 5 random numbers in your head and proceed to write out the the numbers under he date at the top. Add the two numbers together using mod10 addition.

Now, chain add the seed you just made with the date and your 5 random numbers. This should make 10 digits in a small box next to your serialized password. You will take this number and add it to the serialized number. Use mod10 arithmetic again. You should now have a seemingly random number. You will chain add 30 digits under it.

The original 10 will be the transposition key. Transpose from lowest to highest order 7 rows or 21 digits.

Use this as a key for transposition, I recommend 3 groups of 7 to ensure you write all of the numbers.

Using the Polybius square, write your letters underneath. Once you've finished your message transpose it.

You will notice with the cipher it is easy to make the mistake of forgetting one of the transposition columns, you will also note that with the chain addition, one small error can propagate through the whole stream corrupting more than just one digit.

History

It is recommended that you don't use the same key twice or send the same message using a different key. This is very similar to what the Germans used in ww1, it is a well known cipher in the encryption community. This will be a medium grade cipher if you send a lot of traffic with the same polybius key and the same transposition key, as was the error the Germans made. But they changed their transposition and polybius daily. We can change the transposition key with every message.

>>920

So, now that we can do a single columnar transposition, why not do two? That's what everyone has thought of in every military out there. It's simple, it works. Still has the same drawbacks as a single transposition.

This time we're going to need to make 50 digits of PRNG instead of 30.

We're going to use English here instead of using substituted text. This makes it easier on the operator to tell if the message came through.

Now, we're going to take 20 digits, or 4 columns in lowest to highest order again and write that out.

This will be your first transposition key, then we will write out our message under this. We will then go a few rows down and write out a second transposition key using the unused columns, from what is left from the lowest to highest order select for more columns.

See on the second transposition where I have that little pyramid under the 1? I am going to find the lowest number furthest to the left and make a no-go zone for my text. Make sure to compensate for any line breaks, like I have with mine. Begin to transpose from the first key into the first spot on the left. Fill up the go zone on the left first before filling up the nogo zone on the right. Also, this has to be in complete accordance to your cipher text size.

Once everything is filled in under the second key, just transpose again. You should finally have some real garbally ass gook down in the bottom.

Now instead of using a polybius square we're going to use straight English text just because its easier on the cipher operators. I recommend that you have at least 100 digits of text, this is because you can anagram English looking for letters like THE or something in the jumbled text and try to work out the key. More text enciphered more possibiliteies to start from. When using quatsch make sure you use reversed anagrams or something to throw off the lead of the cryptanalyst. The letter Q is only followed by U in English, writing Q on one side and putting u on the other side will help confuse the cryptanalyst.

>>921

This is one of my home brews, what if you were to encorporate a geographical position with a random key? For example if you have

ABCD

If you chose A with an even key number it made you select the letter to the right, which is B, odd, to the left, D.

What if you were to expand that into all directions, up down left right and diagonal in every direction? This is what you would get.

PRNG

We use a 20 letter key instead of 10, this gives us more randomness and the ability to change up the key gen so its less apparent. 0's are ignored. We ill take the key, and use that to find the position of the ciphertext digit based on the position of the plaintext digit. To the top left we can see where each number corresponds. 1 to the top left, 9 to the bottom right, 5 keeps the ciphertext digit the same to prevent against attacks like enigma. 1/9th possibilty for everything seeing as 0 is removed from the equation.

When transmitting this message by voice

. = dot

? = querry

- = hyphen

/ = oblique

Once you've finished writing everything down, it helps to have a second sheet of paper so you can solve by row and then write it out in 5 figure groups after solving the cipher text.