Viginere Cipher

Well I have been studying cryptology for a few days, and it took me a while, but I realized the XOR cipher is nothing but a Vignere cipher except in this case we already know what XORs with what to equal what.

Now I finally understand how to apply a frequency analysis to capture the key.

I'll explain:

Plaint text: THE SUN AND THE MAN IN THE MOON
I will remove the spaces for purposes I'll explain later...

Plaintext:THESUNANDTHEMANINTHEMOON
Cipher text: DPRYEVNTNBUKWIAOXBUKWWBT
Key: KING

NOTE: The ciphertext is not XORed as I wanted you all to see the characters.

Anyway the key is reused which means it is possible to count the coincidences of any repeated characters.... I will demonstrate.

KINGKINGKINGKINGKINGKINGKING - that's the repeated key
THESUNANDTHEMANINTHEMOON
DPRYEVNTNBUKWIAOXBUKWWBT - the sequence BUK comes up twice.

So now we know that the distance between the two BUK's must be a multiple of the key length. We start at the first B and count... BUKWIAOX.. before we get to the next B and we find that the length of this space is 8 which means that the key length is a multiple of 8.

So the key can either 1,2,4,or 8 which drastically narrows down our search. Now we know that the key can only be 8 chars long at most. Now if we had the table of substitution it would be possible to try different combinations of letters till we found one that made sense.

Is this here to brainfuck us noobs?

Originally Posted by ilovecookies

Is this here to brainfuck us noobs?

I think so.

All I understood is something about knowing the the key to some code can't be more then 8 chars....

Originally Posted by ilovecookies

Is this here to brainfuck us noobs?

Definitely.

I actly got the little example from another site. Google Vignere cipher... you can't miss it. What I really want to do is learn just some common encryption algorithms used in application software. And how to examine codes to determine what kind of encryptions they're using. Otherwise I'm just shooting in the dark.

Anyway I had some trouble trying to understand exactly how this method works. But I thought the site did a good job of explaining it. I was actually going to correlate it to XOR and come up with my own example, but their appears to be a slight flaw in my code. I'll fix it then post some more examples as well as smart (non-brute force) ways of figuring out a Vignere cipher.

I'll I explain it in a lil more detail once I get my code to work and can get some realistic examples.

Originally Posted by why06

Definitely.

I actly got the little example from another site. Google Vignere cipher... you can't miss it. What I really want to do is learn just some common encryption algorithms used in application software. And how to examine codes to determine what kind of encryptions they're using. Otherwise I'm just shooting in the dark.

Anyway I had some trouble trying to understand exactly how this method works. But I thought the site did a good job of explaining it. I was actually going to correlate it to XOR and come up with my own example, but their appears to be a slight flaw in my code. I'll fix it then post some more examples as well as smart (non-brute force) ways of figuring out a Vignere cipher.

I'll I explain it in a lil more detail once I get my code to work and can get some realistic examples.

Lol he is to smart for me i dont get it ahhhhhhhhhhhh

I <3 kthxbai

Brainfucked.

Hey can you explain a mersenne twister?

Lol coz there are endless possibilities of applications in gamehacking

Originally Posted by falzarex

Hey can you explain a mersenne twister?

Lol coz there are endless possibilities of applications in gamehacking

Hmmm... I'm not familiar with that, but I do know it relies on chaos theory. That is that an extremely small change in the initial conditions can lead to a radically different affect. Using very simple equations it's possible to create mathematical graphs of infinite complexity. I don't have a good backing in the equations so I can't elaborate. But they are pretty neat.

I actually have a fractal image as my wallpaper, which are images created by these equations. Look at this:
Beautiful right. There is a strong argument that nature stores things like biological data in this format. So you see a relatively small instruction can make an infinitely complex structure and yet repetition is still found (.aka symmetry) as with the Madelbrot video, one of the most famous fractals.

Oh about your Mersenne twister. I would have to look up the specific equation, but I don't see the point since you can most likely just call rand without knowing how it works. This is can be used for encryption I suppose, to provide a fake randomness, but you have to remember the results of the random number generator are completely predictable, if you have the right initial information.

There. I think I did a good job of not answering your question.

Another 1 just 4 fun:

Yeah apparently there are some examples online
the pokemon engine is one good example(I know ROFL) it combines current time readings with the twister equation to form infinitely random stuff(don't know much) but apparently some people managed to reverse the process and create a god-tool that can determine or generate certain special events that are normally random
So it is reversible but extremely time consuming

Viginere Cipher

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