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The Prison Guard With a Gift for Cracking Gang Codes
- Fundlab 13y agoInteresting
- comex 13y agoSee also: "Is there a secure cryptosystem that can be performed mentally?" http://crypto.stackexchange.com/questions/844/is-there-a-secure-cryptosystem-that-can-be-performed-mentally http://crypto.stackexchange.com/questions/844/is-there-a-sec...
- mistercow 13y agoThat makes me wonder if any gangs have used Solitaire. Weaknesses aside, it seems extremely plausible that you could actually share the keys in prison and execute it. And a 225 bit key is nothing to sneeze at.
- telephonetemp 13y agoOn the other hand a substitution cipher is more resistant to user error when encrypting or decrypting since such an error only affects a single character. In secret prison communication you might not have the time to double-check your encryption. I wonder if imprisoned gang members have access to cell phones, though. They probably do. You could run actual strong crypto even on a J2ME device (or a gaming console, or a programmable calculator, or an MP3 player etc.) and I'm sure there's plenty of people you could hire to write a custom-designed, one-of-a-kind bespoke cryptographic app for a gang.
- mistercow 13y agoI was under the impression that in prison, time is the one thing you have plenty of.
- telephonetemp 13y agoTime when you can fiddle with cards and write down cryptic series of numbers without attracting undue attention is probably scarce.
- mistercow 13y agoThe cards just look like you're playing some form of single player game (hence the name). If you had a journal to write in, then with some practice, you could pass it off as idly playing the game while thinking of what to write.
- DanBC 13y ago> write. How many prisoners have free access to pens or pencils? (Not snarky, I really don't know)
- evacuationdrill 13y agoIn a recent thread on reddit, a former inmate listed what was issued in county/state/federal, and paper with a pencil or a pen with a rubber body was in all of them.
- telephonetemp 13y agoCan you give us a link?
- evacuationdrill 13y agoI wish I could, but I can't remember what the thread was about originally. I tried searching, but I can't find it.
- EdiX 13y ago> I wonder if imprisoned gang members have access to cell phones, though. They probably do. No, they don't. Most countries (including USA, AFAIK) restrict inmates phone communication with the external world.
- panarky 13y agoCell phones and other contraband may be prohibited, but they still exist in prisons. State prison records show that for the first seven months of this year, corrections officers have seized 319 cell phones from inmates [in Ohio's] 28 prisons. http://www.cleveland.com/metro/index.ssf/2013/08/ohio_prison_system_sees_spike.html http://www.cleveland.com/metro/index.ssf/2013/08/ohio_prison...
- mistercow 13y agoI'm sort of surprised that, rather than seizing them, they don't just put an IMSI catcher there and listen in on inmates' illicit calls.
- strictfp 13y agoSo, a simple substitution cipher? Should be trivial to crack.
- smcl 13y agoFor this guy yes, but for not necessarily everyone. The messages don't seem to be particularly long so it's unlikely a frequency based attack could work. Also if it is then these guys will not exactly be using the Queen's English so they'll likely have a different letter frequencies for their dialect. This lad in the article has a real knack for it though, I guess he knows the subject matter pretty well (i.e. knowing the kind of things people will be saying in certain scenarios, the word choice, how they address each other, how the gang hierarchies work etc) and has a good mind for the kind of on-the-fly ciphers that these gangs employ.
- Patrick_Devine 13y agoWhat kept nagging me while reading the article was why aren't law enforcement officials taught to crack these types of codes? If your job is law enforcement, just having a simple understanding of the types of simple cyphers which criminals use seems like it would be invaluable. My next thoughts were a. "Would a reasonable set of law enforcement officials actually be able to learn how a simple cypher worked?", b. "If a large enough percentage of law enforcement could crack those types of codes, would the gang members come up with more complex cyphers?", and c. "How hard is it to smuggle a one time pad into prison?".
- mturmon 13y agoYou would not have to limit yourself to a frequency attack. You could also match decoded text against a word dictionary.
- maxerickson 13y agoFrequency analysis works against a few dozen characters.
- tripzilch 13y ago
- smcl 13y ago"The messages will disparage other gangs in a backhanded way. In a Blood letter, you’ll see that the letter C is usually crossed out or has a slash through it out of disrespect for the Crips. And to praise themselves, they’ll write a B with an up arrow." It's so strange that there's these very serious gangs responsible for traumatising large areas in US cities, yet they do massively petty things like writing a "WE R KOOL" up-arrow beside a 'B' in their correspondence, and crossing out a 'C' (if they're a Blood that is). I can't connect that juvenile elementary school behaviour with gang violence and shootings, it seems so contradictory.
- INTPenis 13y agoMaybe because many of them dropped out of elementary school due to poverty and gangs.
- thaumasiotes 13y agoGang violence is the default state; it is the behavior that children will naturally develop without being socialized (and return to, whether child or adult, in the absence of authority). You're observing that these gang members haven't been socialized out of instinctive self-congratulation in their writing, or out of instinctive pack behavior. I don't see the disconnect.
- sneak 13y ago> (and return to, whether child or adult, in the absence of authority) [citation needed]
- narag 13y agoI haven't any. But Lord of the Flies is nice as food for thought. Also there's a film based on the book.
- bediger4000 13y agoFiction, both of them. So no references for violence as a default state of society so far, just aphorisms and "common knowledge".
- harywilke 13y agoReminds me of The Wire episode "The Pager" (Season 1, Episode 5) where the dealers were using a code to send numbers to pagers. http://www.youtube.com/watch?v=DQBlq45c1T4 http://www.youtube.com/watch?v=DQBlq45c1T4 (clip shows the reveal of how the code works)
- mistercow 13y agoWhy do they have a human doing this? We have computers now, and solving this kind of cipher is a Solved Problem. What this guy spends days on, a computer could do in milliseconds.
- phaer 13y agoI guess the problem is domain specific knowledge, user smcl did write something about that below.
- 16s 13y agoLaw Enforcement is a very tight knit community. They trust each other and that trust builds over the years. They are almost like a family. And apparently, this is their go to guy for gang codes.
- josephcooney 13y agoThis seems like "cryptanalysis, circa 1600".
- bediger4000 13y agoIndeed. Caesar Ciphers seem to be the hardest it gets. Did you notice that this gang cryptanalyst actually described the famed "ROT-13" as a method the gang members used?
- 16s 13y agoTriple rot13 (like Triple DES) is government approved. echo -n word | \ > wm --rot13 --words stdin | \ > wm --rot13 --words stdin | \ > wm --rot13 --words stdin result: jbeq However, the result is the same as a single round. echo -n word | wm --rot13 --words stdin result: jbeq
- colanderman 13y agoOne of the codes I worked with had multiple symbols for each letter. We have 26 letters in the English alphabet. But this code system had 40 symbols. The letter “E” had three different ones. The letter T had two and so on. That’s a very complex code. Interesting; they're trying to flatten out the code distribution…
- b0b0b0b 13y agoReminds me of http://math.uchicago.edu/~shmuel/Network-course-readings/MCMCRev.pdf http://math.uchicago.edu/~shmuel/Network-course-readings/MCM... using MCMC to break a prisoner substitution cipher.