Cryptography

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A project I’ve been working on 

“Hello. We are looking for highly intelligent individuals. To find them, we have devised a test. There is a message hidden in this image. Find it, and it will lead you on the road to finding us. We look forward to meeting the few that will make it all the way through. Good luck.” That message, signed “3301,” appeared on the underground message board known as 4chan two years ago. It was mysterious, cryptic and sparked a global Internet mystery that has yet to be answered to this day. (via The Internet’s Cicada: A Mystery Without An Answer : NPR)

  • “It’s like a Dan Brown novel if Dan Brown could write this well,” freelance writer Chris Bell tells NPR’s Arun Rath. Bell wrote about the online mystery for The Telegraph. “It’s beyond the realms of my intelligence and beyond the realms of any individual’s intelligence to do this.”
  • Thousands of peopletook on the challenge.
  • To code-breakers who dwell in this world, it was simple in the beginning. The first puzzle used a technique called steganography, concealing a message or image within another image. Hidden inside that first seemingly simple image — those black words on white text — were many more pictures, codes, clues and the reoccurring image of a cicada. That’s what gave the mystery its name: Cicada 3301.

anonymous asked:

Would you be able to explain how a paper enigma works? (Usually made with a Pringles can). I'm a little lost and not finding a lot of info on how to use it....

Yeah, I’ve never built one myself, but I have made simpler cipher devices. Here’s a picture from a site about them so others can see what we mean:

Basically it’s the guts of an Enigma machine, printed on paper and taped around a cylinder, a Pringles can as you mentioned. The bar to the far left and right are the reflector and the key/light board of the machine, and the three pieces in the middle with letters on them are the rotors. The gray bars to the left and right mark the starting position of the machine. So in this picture the Enigma message starting rotor positions are FHL. Now you just replicate the motions of an Enigma machine with your hands.

1. Turn the left most wheel one click towards you (the Enigma was an electromechanical machine, so pressing a key down made the rotors move, then when the key reached its lowest point a circuit was created that allowed electricity to pass through the machine’s parts and light up the enciphered result of that keypress. So you have to move the rotor before enciphering the first letter, or else the entire message will be one letter off each time.)

2. Let’s say the first letter of your message is W. Find W on the cylinder on the right side, which is your keyboard, and follow it over to the right most rotor. In this pic you can follow the nice red line there over to P, where the electricity would exit the right most rotor and enter the middle rotor. Following that line we see that the electricity exits the middle rotor at H, and exits the left most rotor at G. It then is bounced back by the reflector, the left most piece of paper, and although we can’t see the line in this picture, it just goes back the same way, following the line through each of the three rotors, until it arrives back at the keyboard.

3. When it arrives back at the keyboard, it will arrive at one of the 25 letters that isn’t W. Let’s say you are encrypting a message, and the lines lead back to Z. Plaintext W = Ciphertext Z, and if you were to follow the line back, you would of course get the reverse. The reflector and key/light board circuit make enciphering and deciphering the same process, just set the rotors to FHL and move the left rotor, then feed your ciphertext back into the machine and you get the plaintext message.

4. I assume a plugboard can be easily simulated. It is simply an alphabet of 26 characters, with zero to ten plugs connecting some of the letters, such that if W was plugged into A, then the W at the start of your message would first be turned into an A before entering the rotors, and the steps we did above would give a completely different result.

Doh… forgot to say, there are markings so you know at what point a rotation of the left most rotor causes the middle and right most rotors to rotate one position.

vengeful-half-vulcan  asked:

This is a code. Your blog came up when I searched "Cryptography." Any chance you could help out? espnd hw of lsepe i mhi ni iwhottu iwll in rcae thwa satr reoasn nda tseals ym be twha be ewest wlil my ym elif tsar lilw fiel herat ktae to

Hello- I’ll do my best! (@ those on mobile - apologies for the long post )
Firstly, the frequency analysis of this is unusual given that all the original common letters of a, e and t have their usual percentage of appearance - This means that they are likely being used in their original context and were not substituted for other letters. This is shown in the following graph:

Considering this, I used Word Unscrambler in order to generate the next part. The one irregularity is the hw which of course rearranges to mean nothing.  Now I’m going to take a guess and assume hw may be a typo and is meant to be he given the him mentioned in the message.

“Spend he of Sleep I him in without will in race what star reason and steal (this particular word could be something else like least or tales or even tesla!) be what be sweet will my my life star will life heart take to”

My, will, star and life are the most common words. These words have heavy connotative meaning. It is important to remember the context of the message is just as important as the code itself. Who was the code intended for? How was it meant to be received? What sort of person is sending it?

A rather dark interpretation that manages to fit all the words evenly is the following. This is unlikely to be the original message though given the immense multitude of combinations that emerge when rearranges the letters. However this deconstruction could potientially led deciphering the original message -  especially once we learn the context.

My star
I will sleep without him 
He will steal my heart and race to take my life
Spend in life what will be sweet
Star, what of reason.

Other versions could easily follow this pattern: 

I will spend my life with him
My heart will race and life will be sweet

I will take my life without him
He will be sweet reason to sleep
Take my life and my heart

He is my star and my heart in life 
With him I will spend my life without reason

cxmet  asked:

Hey basic question, but if you get a cipher and it's just a bunch if scrambled letters with spaces here and there or maybe even just one big long jumbled word, how do you go about narrowing down what type of cipher might decode it? And what if you get numbers instead?? Sorry if this is really long or difficult or whatever, I just always have trouble initially decoding when there's no hint given as to what cipher was used. Thank you!!!

No problem, I’m happy to help! I’ve added links on certain terms to make the explanation easier to understand. Ciphers can be intimidating but it’s important to remember they are never impossible to solve. The solution may just be temporarily unknown and these methods can hopefully help bridge that uncertainty.

  • Frequency analysis is one of the first steps to take. That means you analyze how frequently certain letters appear within the language overall compared to the message. This is the easiest way of determing what type of cipher is being used. If the letters doesn’t fit this pattern then something more advanced than simple substitution is occuring. 

  • Identifying the cipher is important or at least noting similarities. In order to make this process easier, you’ll need to familiarize yourself with different types of ciphers. Once you know what they look like and how to solve them, you will be able to recognize them. Popular ones such as: Caesar, Monoalphabetic, AtbashVignere. As for numbers, the A1Z26, Binary, and Beale would be a few that could be used.
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Today, we’re going over some encryption techniques that are used to keep information safe, private, and secure!

  • Christopher: Cryptography is the science of codes.
  • Alan: Like secret messages?
  • Christopher: Not secret. That’s the brilliant part. Messages that anyone can see, but no one knows what they mean, unless you have the key.
  • Alan: How is that different from talking?
  • Christopher: Talking?
  • Alan: When people talk to each other they never say what they mean. They say something else. And you’re supposed to just know what they mean. Only, I never do. So how is that different?
  • Christopher: Alan, I have a funny feeling that you’re going to be very good at this.

Today I learned there’s a thing called a “perceptual hash”, which is hard to invert like a regular hash, but is relatively continuous so that small changes in the source lead to small changes in the hash.

It’s used for fingerprinting media files, and it’s being used in the facebook anti-revenge-porn thing.

And it’s of course vulnerable to exactly the sort of attacks you’d expect a hasing algorithm where minor changes in the input create only minor changes in the output to be vulnerable to. So it generally can’t be used if the hashing algorithm is made publicly available. That’s why Facebook is doing the server-side hashing.