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OpenSesame – A device that can open fixed-code garage doors in seconds

samy.pl

21–30 of 111 posts

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#21
post #17

Earlier quoted context omitted.

Exactly. Lots of people don't realize that most of their door locks are there to keep "normal" people out, because dedicated criminals are typically going to find a way in.

Locks keep honest people honest.

Locks reduce the instances where dishonest people can exercise dishonestly without repercussions. But that's what much of life is about, reducing the occurrences of negative outcomes. Elimination often isn't possible or feasible.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#22
The Wikipedia article doesn't mention this, but the de Bruijn sequence can be computed greedily.

Start with 000...0, keep appending the largest digit possible that doesn't produce a code that's already been used and you'll go through all the codes.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#23
post #18

Three weeks ago I reverse-engineered my garage door opener wireless protocol. I probed the remote's PCB with a Saleae logic analyzer and found it was a 12-bit code ASK-modulated at 390 MHz with bits encoded as sequences of 10 kHz and 20 kHz pulses. I bought a $13 spare remote to hack it and control the RF transmitter section from my computer through an FT232 sending the ASK signal. I just cut off the digital signal t…

There's information about it online now, thanks to your post! I came here wondering what frequency ranges and encodings are at work, and now I know.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#24
post #12

Might as well post a more direct link: http://samy.pl/opensesame/

The "source code" of http://samy.pl is quite interesting /* No source for you! *// /.source.replace(/.{7}/g,function(w){document.write(String.fromCharCode(parseInt(w.replace(/ /g,'0').replace(/ /g,'1'),2)))});

There is a huge amount of whitespace is the page source. A mix of tabs and spaces. The page is encoded in that. Have a look in the inspector to see the decoded result. It's a bit like this: https://en.wikipedia.org/wiki/Whitespace_%28programming_lang...

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#26
post #5

Earlier quoted context omitted.

Criminals use lock picks when you don't want someone to know that they broke in. Most criminals are the "snatch-and-grab" type. They are more likely to look for an unlocked window or just break a window. Oh, and deadbolts are pretty easy to pick.

Or just kick the door down.

So true. I once lived in an apartment block where a lot of the other apartments on my floor were burgled one day.

The locks did.. nothing. The thieves simply kicked the doors until they splintered at the lock. In fact, one door even snapped clean in half, so it ended up looking like a stable door, with a lower bit no longer attached to the lock which was now opening freely.

I'd wager it took them a similar amount of time to do this as picking a lock would have taken for someone experienced, and with far less training.

It taught me a very practical lesson about security. You can spend a lot of energy engineering the perfect lock, but always be aware that there will likely be obvious (once they've happened at least), perhaps very course, hacks which make that brilliant lock totally redundant.

The parallels to software security are obvious. To loosely quote Richard Campbell, it doesn't matter how strong your password is, if a truly determined bad guy wants to get at your data, they'll just use a wrench ;-)

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#27
post #18

Three weeks ago I reverse-engineered my garage door opener wireless protocol. I probed the remote's PCB with a Saleae logic analyzer and found it was a 12-bit code ASK-modulated at 390 MHz with bits encoded as sequences of 10 kHz and 20 kHz pulses. I bought a $13 spare remote to hack it and control the RF transmitter section from my computer through an FT232 sending the ASK signal. I just cut off the digital signal t…

Well, it seems that from the point of view of Genie, if it's required to send the correct code N times in a row, acceptance should be aborted if that is interspersed by any wrong code. In that case, a De Bruijn sequence wouldn't work.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#29
post #21

Earlier quoted context omitted.

Locks keep honest people honest.

Locks reduce the instances where dishonest people can exercise dishonestly without repercussions. But that's what much of life is about, reducing the occurrences of negative outcomes. Elimination often isn't possible or feasible.

This is a much more accurate than the old "Locks keep honest people honest" saying.

If you consider yourself an honest person, ask yourself how many times you've tried to open doors to random houses as you walk down the street. If you found it unlocked, do you rob the place?

If you need a lock to keep you honest, you may want to reevaluate your values.

Re: OpenSesame – A device that can open fixed-code garage doors in seconds

#30
post #12

Might as well post a more direct link: http://samy.pl/opensesame/

The "source code" of http://samy.pl is quite interesting /* No source for you! *// /.source.replace(/.{7}/g,function(w){document.write(String.fromCharCode(parseInt(w.replace(/ /g,'0').replace(/ /g,'1'),2)))});

Nazi...
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