Monday, March 21, 2005

Old tricks and new

Yesterday, while waiting for the clouds to break and the promised ~20C temperatures (they didn't — it stayed about 10C) so I could enjoy some gardening that wasn't heavy lifting, I was up in the loft for a while. I came down, and left the ladder in place unattended for a few minutes before shutting the trap door and putting the ladder away.

And then I heard a cat wailing.

It took a while to realise that Penny had, for the very first time, bounded up the ladder and gone into the loft; and she was standing on the hatch, and calling for attention.

Earlier, I was replacing my bike lock - having lost the key to my previous one, I picked up a moderate/high security (level 6) combination lock, with 10^4 combinations. Setting the combination involved removing the shrink wrap, keying the factory set 0000 to open, unlatching the wheels, setting the desired number, and relatching.

So I slid the pin in, twirled the wheels, and then dialled back my combination. And it said “shan't”.

I tried all the adjacent combinations. No luck. So then I started from 0000 and started working through. During the first 1000 combinations, I came to a point where the pin felt very loose; so I tried the top-most wheel, still on zero, and within a turn, I had the combination. The number dialled was out by 0 in one digit, 1 in one, 2 in one and five in the other from the one I'd set.

Now, unlike many cypherpunks, I've not really gotten deep into lock-hacking; but I was gratified to discover that something I'd done before as a student to crack crappy 3-digit chains (to move the insecure device from one wheel to the other as a friendly hint to those relying on such) transferred to a much higher spec. of lock.

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