The page for the Featuring process can be found here.ĭespite having something of a girl's name, Rejewski was a veritable geek hero, solving the wiring of the German Enigma machine using some funky maths. CIPHER TEXT FREEThe Wikipedia article on Polish mathematician Marian Rejewski is currently going through the process to become a so-called " Featured Article", vetted entries that are eventually promoted on the main page and elsewhere.įeel free to read the article and add any comments. Still, a good old-fashioned pair of bolt cutters is less hassle. I did some tests (on a lock of my own, of course), and if you observe several of these states, and you have a reasonably accurate model of what weak scrambling method is being used, you can whittle down the possibilities pretty quickly. As a result, the state after a half-hearted scramble still reveals information about the secret combination. On university campus, I've noticed that many people in a hurry don't really scramble their combination locks (for cycles, normally) very thoroughly - maybe a quick flick of the dials with the thumb, or something of that sort. Herivel's tip reminded me of combination locks, of the type with rows of dials of digits. It was Hut 6's lifeline for a few months in the Summer of 1940 after the Germans had changed their indicating procedure, obsoleting the Polish techniques then in use. If you're interested, I wrote up the details in a Wikipedia article. Dubbed the Herivel tip or Herivelismus, it relied on Enigma operators taking a shortcut and not randomising the rotors after having set up the machine. It seemed to have the desired effect.īletchley Park has announced a forthcoming lecture by WWII veteran codebreaker John Herivel, a Hut 6 mathematician who, within weeks of arriving at BP, had come up with a nifty bit of lateral thinking to help solve Enigma. After reading it, Churchill, who was a keen consumer of Bletchley Park's product, memo'd his staff with the terse but unambiguous " Make sure they have all they want on extreme priority and report to me that this had been done." With "ACTION THIS DAY" stamped above it in big letters. Milner-Barry delivered the letter in person to 10 Downing Street in October 1941. The letter, which was also signed by Alan Turing, Gordon Welchman and Hugh Alexander, outlined their needs for a relatively small number of additional clerical staff in order to carry out their work effectively. He is particularly remembered for co-authoring a letter directly to Winston Churchill requesting more resources for the codebreakers, bypassing the apparently ineffectual leadership at Bletchley Park. Last week I revamped the Wikipedia entry for Sir Stuart Milner-Barry, chess player, civil servant, and the head of Hut 6 at Bletchley Park from October 1943. Because of above, the plaintext must contain less information than can be encoded by the specific ciphertext size after all.Cipher Text is back! Apologies for the lack of activity here for most of 2006, hopefully I'll be posting more frequently in 2007. Attacks on compressed audio streams or HTTPS connections are certainly not just a theoretic threat, they are all too practical.Īnd beware that even without compression, the ciphertext size will always leak information about the plaintext. However, you should keep in mind that the size of the resulting ciphertext may leak information to an adversary. It is possible to use a compression algorithm to compress specific types of messages in case your set of messages is smaller. And because of the pigeon hole principle, it is of course impossible to have smaller ciphertext for all possible messages. If you have a specific set of messages that increases the ciphertext then obviously they are distinguishable from the other messages. This means that any message of the same size should return ciphertext that is indistinguishable. Note that a modern cipher should be IND-CPA secure. As most modern ciphers are bit/byte oriented that means that all possible messages of a certain bit/byte size are possible. It should be possible to input any kind of message. Generally encryption acts on input that cannot be compressed.
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