Archive for category: Cryptography

Visual Cryptography

November 20, 2013 | Cryptography, My Projects | By: Mark VandeWettering

I read an interesting article the other day. I’ll skip to the end to show you the result. Check out this pair of binary images: Not too fascinating, huh? If you print both images out on transparency though, and stack them together, you’ll get this… Hopefully that worked (with my limited CSS skills, I don’t […]

Can we go beyond WSPR? An idea for beacon operations on amateur radio.

September 13, 2011 | Amateur Radio, Cryptography | By: Mark VandeWettering

I was interested in WSPR and visual MEPT oeprations for quite some time. I operated both a beacon and a QRSS aggregator on 30m for a while, but I grew a bit tired of it, and it’s been silent for a year or so. But I haven’t stopped thinking about them. In fact, I’ve had […]

Donald Michie, Alan Turing, Martin Gardner, and Tic Tac Toe

August 28, 2011 | Computer Science, Cryptography, Games and Diversions | By: Mark VandeWettering

As anyone who reads my blog with any regularity will tell you, I like to read and learn new things. The problem with being self taught and also easily distracted means that you often learn a great deal, but don’t always perceive the connections and scope of what you are learning. I found another example […]

Neat article on William Friedman and Steganography

March 28, 2011 | Cryptography | By: Mark VandeWettering

William F. Friedman is a name that might not be familiar to you unless you are a bit of a cryptography nut. Of course, I am a bit of one: I have a couple of long technical notes that were authored by Friedman on the cracking of some complex WWI era ciphers. But I must […]

Demo of Enigma and the Turing Bombe at Bletchley Park

March 15, 2011 | Amateur Radio, Cryptography, My Photos, My Projects | By: Mark VandeWettering

Carmen and I just got back from a trip to London, and we had a blast. One of the geekiest things we did while there was to take a day trip by train out to Bletchley Park to see the site of the codebreaking efforts by the British during WWII. As any long time reader […]

Colossus: The secrets of Bletchley Park’s code-breaking computers

January 15, 2011 | Books I Read, Cryptography | By: Mark VandeWettering

As long time readers of my blog might remember, I’ve been fascinated by old cryptographic machines. I spent quite a bit of time tinkering around with them back when I was working on Simon Singh’s cipher challenge in his book. In particular, I spent a considerable amount of time reading up on the German Enigma […]

10,000 Monkeys Typing…with a Unix/sh challenge…

July 27, 2010 | Cryptography, Programming Languages | By: Mark VandeWettering

I was testing some code that I wrote for analyzing cryptograms, and decided that the easiest way to do so would be to get some random text, drawn from the letters A-Z. A moments thought yielded this method, without even programming anything: tr -d -c A-Z < /dev/urandom | dd ibs=10000 count=1 The tr generates […]

Crazy Optimization of Chaocipher…

July 15, 2010 | Cryptography | By: Mark VandeWettering

Okay, this is a minor hack, but I thought it was fun, so I thought I’d write it up here. My original code for simulating the Chaocipher machine proceeded as follows: it found the character in the plaintext wheel (by linear search), then rotated each wheel to get the plain and cipher text entry to […]

Typos in Exhibit 1?

July 12, 2010 | Cryptography | By: Mark VandeWettering

WARNING: if you are working on this code, this article contains spoilers which may blunt your own intellectual satisfaction in working on it yourself, including some recovered keys. Okay, I’m home, and feeling pretty jet-lagged, so this might be wrong in some way that additional sleep will reveal, but I wanted to get this out […]

Progress on Exhibit 1

July 10, 2010 | Cryptography | By: Mark VandeWettering

Okay, I think I’ve figured out the problem with my code that back propagates cipher wheels to the beginning of the code, and ran it on Exhibit 1 again. It actually matches 603 characters of input, then stalls, after searching 1.8 billion cipher encoding possibilities. I am now trying to figure out if it is […]

More on Chaocipher…

July 9, 2010 | Cryptography | By: Mark VandeWettering

Well, I didn’t have much time left to work on Chaocipher last night, so I left it running on Exhibit 1. It claimed to recover a key that allowed it to match 601 characters of input, but found no better match. But it also uncovered an error in my code. It doesn’t appear that the […]

Progress on the Chaocipher…

July 8, 2010 | Cryptography | By: Mark VandeWettering

My brain has got a bug now. It’s called Chaocipher. Despite the fact that I’m spending my days off with my family, I find that in my odd moments my brain keeps leaping back to Byrne’s cipher. The other night I implemented the basics of key recovery using a chosen plaintext attack (if you have […]

Visual Inspection of Chaocipher Output Implies Weakness

July 6, 2010 | Cryptography | By: Mark VandeWettering

So, first thing this morning, before I had even had coffee or blinked the sleep from my eyes, I decided to try a chosen plaintext attack against Chaocipher. I created a file consisting entirely of 2000 A’s, and passed it through Chaocipher. Here is my output: PKLSD MAVZC UXHEP KLSDM AVZCU XHEPK LSDMA VZCUX HEPKL […]

An Implementation of Byrnes’ Chaocipher

July 5, 2010 | Cryptography | By: Mark VandeWettering

Okay, insomnia got me, so I went ahead and implemented it in Python. It appears to work reasonably well, at least it successfully deciphers their test message. You can specify the key by specifying the -c and -p options, which are the settings for the cipher and plain wheels. You should pass a permutation of […]

The Chaocipher revealed! from Cipher Mysteries

July 5, 2010 | Cryptography | By: Mark VandeWettering

Stumbling back through articles in Slashdot, I found a pretty nifty article on one of my favorite subjects: historical cryptography. The story goes that back in 1918, a cipher system/machine was invented by John F. Byrne. Rumor says that it was very strong, and yet could be implemented using a mechanism that would fit in […]