“the PM is on the green scrambler”

Reasons for use


Secrecy: you don’t want people to know you’re using a code, so then they won’t (A) realize you’re up to something, and (B) start breaking the code. Another worry is being caught with encoding/decoding materials (like a one-time pad) which would be incriminating

Security: you don’t want something easy to break, and need something easy to change so that a break won’t put you out of commission for a long time.

Easy to use

No equipment
Fast encoding/decoding
Easy to learn

Hard to mix up


A ‘closed’ set of codes is easier to manage for one-time-pad
An open code is more flexible to encode anything, but could be harder to use, or be easier to break.


Need to make sure that you can’t be spoofed if a member is caught and compromised, or if knowledge is intercepted


Can be useful to prove you weren’t up to anything really bad, or can be bad news if the judge doesn’t like what you were doing.


SMS (can be recovered from the phone company)

Voice (can be overheard)

MMS (hard to intercept, but requires taking a picture of something)

Data (requires an application)


Duress code – to use when you’re under surveillance and can’t communicate freely, and a second to say ‘disregard future communication, captured’ (has to sound innocuous)


Message in a message

Hide a message in another message, either by coded words or phrases, or with tones!
See http://www.hulu.com/watch/90211/lost-through-the-looking-glass-part-2
The code to turn off the jamming equipment is “good vibrations’ played on a keypad.

The code: DTMF signals in a voice call. Voice calls are seldom recorded, and extraneous button presses occur sometimes, and therefore would be unlikely to arouse suspicion.  And the medium can be used for both encoded and clear transmission, and it’s synchronous.

Sample DTMF codes:

1: yes

2: no/not

3: acknowledged

4: go to predetermined location

The DTMF tones would have to be set securely beforehand, therefore making this system potentially vulnerable if the system were discovered.  It has a built-in anti-spoofing mechanism in the voice of the users being distinct.  It is able to be cracked through analysis, although proper use would make this more difficult, as would changing keys.

This would be ideal for communication in a small group, for a closed set of signals.


In America, radio listen YOU!

Listening to the police radio is an interesting (and legal) experience.  In one sense it makes sense that they let citizens listen in as a check on police abuse.  I’m surprised though, because if upstanding citizens can listen in for fun or for university projects, criminals can listen in to see if they’re about to get caught and can act accordingly.  If I were the police, I’d be using a scrambled radio system so bad guys wouldn’t know what I’m up to, although that might decrease the happiness of cantankerous old guys.

Listening to the DC Metro police radio, (http://www.rollcallradio.com/feeds/dcmpd.aspx), it’s pretty much what you’d expect.  half ‘football’ codes: “738, we have a 5082 on F street” and half clear communication: “two suspects, black males, one in black jacket and bluejeans, one in jacket and blue jeans.”  I didn’t hear any chatter about donuts.

It’s a pretty good system, combined with the in-car datalinks, it’s pretty spare on communication.  I’m amazed that the traffic on the voice loop is manageable for such a large city, but there’s probably a lot of communication with the datalink which cuts down on the voice traffic (i.e. license checks, etc.)

There must be some sort of tracking for where the cars are, so they can intelligently dispatch, but there may not be—which increases the cognitive load on the police officers, who have to listen to the radio calls for issues in their area.

what’s for lunch

I’m kind of happy to shop at Whole Foods because they promote better school lunches.  I remember my middle school/high school lunches, and, I have to say the foodservice wasn’t great, so I ate peanut butter most days.  And I still love it.
Something has to happen with the food policy in this country, and I hope it will come as a part of the healthcare push.  Generation Y and the following ‘Millenial’ generation face the specter of a decreasing life expectancy compared to our parents, in part due to the weight and diabetes epidemic.
The school lunch was designed when getting enough calories was a priority, and processed food wasn’t as prevalent.  now that processed food is so cheap as to displace real food, it makes financial sense to give the kids reconstituted substitute food product..

you’re not supposed to do that

the guys who looked like retired sumo wrestlers weren’t so happy about me taking this picture:
it’s much safer to shoot from far away and use a long telephoto (Nikon N70/Tamron 28-300mm lens)
some ‘unauthorized video’ – my friend Arthur and some friend of his make a pretty convincing sparring couple, but they were just playing around (this was not scripted or in any way prompted, I just pulled out the SD800 and starting filming)
the last of the street jugglers: making a buck from drivers on W. Houston street.

(not) good enough

Recommended reading:
a stab at explaining the move away from quality, and I agree with their thesis.  And this shift isn’t all bad, in the sense of moving from quality to accessibility.  My D80 is hefty and super flexible.  But it’s hefty and therefore not always in my pocket, like my pocket size Canon SD800 (which is pretty good on the quality front, I must say).  Unfortunately the camera in my cell phone (Samsung Omnia) isn’t quite good enough for me, even though it totally blows away the Iphone’s camera in both flexibility and quality – it has a flash!! [among other useful features]).
 from the Omnia Cam.  Should be more Kodak yellow and dark wood brown!
The thing I don’t like is the shift from quality to quantity.  I want to fix the late 70s vintage Hitatchi tuner under my bed.  If that fails, it goes to pieces for ITP PhysComp projects.  I don’t have a problem with accessibility (it is pretty understandable how to work the thing, and you really have to be lazy to really bemoan the lack of a remote control).  But tinny sound?  unacceptable!
they neglect to mention Ikea’s rather poor environmental record, which was trumpeted to the world recently in The Atlantic: http://www.theatlantic.com/doc/200907/ideas-ikea. Come on Ikea, your stuff is decent and designer-y enough to move forward from the insipid colonial american look, but please move forward on the environmental front!  You’re big, you have good brand equity, and can do an enormous amount to shape customers buying behavior and reduce the environmental impact of your products.
And the switch to Verdana is a poor choice.  http://www.nytimes.com/2009/09/05/arts/design/05ikea.html  I don’t have a problem with Verdana by itself (I use it) but Futura is (A) iconic and (B) part of your brand identity.  Don’t mess with that.  It’s bad business, and annoys customers and design people.


The Blinkenlights! (project 1 for Introduction to Physical Computing):







courtesy of Wikipedia, of course