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Comment by WalterBright | Hacker News Reader

I bet you could examine the keypad for wear. The worn keys (or the shiny ones) are the ones for the code.

In the days before cell phones, a burglar alarm would dial the alarm company. The phone company likes to install the phone box on the outside of the building. The alarm is defeated by an axe to the cable going in the box.

I had a fight with the phone company at my house, as I wanted the box on the inside rather than the outside. They finally agreed on the condition that I maintain the wire to the box.

These days, of course, the alarms use wifi or a cell phone to call the alarm company.

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That only works if there's a single code? I would think many keypad systems assign a code to each apartment (so the one written on the side is not a master key, just Joe in #303).

I've definitely worked somewhere they tell all the users they have individual codes, not to share them, and if there is unauthorized access it can be traced who leaked their code. Everyone gets told the same story and given the same code.

Do your alarms not have an actual - you know - alarm? Or won't the alarm go off if it can't phone home first?!

Here in the UK the alarms make a noise as the absolute minimum. Getting one that is "monitored" by a call center is not standard, especially one that calls the cops if it goes off or a panic button is pressed.

You can get those of course, but it costs extra. I pay something like £40-50 a month for the panic button service that will summon the police, but even then the police won't be summoned if just the alarm goes off without a panic button getting pressed (you can get that, but it is even more expensive)

In my area of London, burglary is a virtually abandoned trade.

Anyone with anything of value works from home at least part of the week. Why risk entering someone's actual house when you can make easy money on drugs, fraud, crypto, bicycle theft, phone snatching, or umpteen other hustles I don't even know about.

Bicycle theft especially. You could easily clear a grand or two a week with zero fear of prosecution.

I think general burglary is heading in that direction across the country.

The things people used to pinch like VCRs, stereos, TVs, laptops just aren't as expensive or sellable now.

Unfortunately if you live in a nice area, they assume everyone has a Rolex collection or loads of jewellery just hanging around. If nothing else they'll take the keys to your cars.

Just look at the prices those bring in the thrift store or the pawn shop. I just bought an HD Roku TV for $50.

> These days, of course, the alarms use...

And the crooks use RF jammers instead of axes.

These days, alarms use quantum entanglement. Beat that :)

I set the Fires of Gondor.

There's enough bandwidth to go around nowadays that alarms can send regular keepalives (which doesn't mean all of them do).

If the keepalives stop coming without a proper disarm signal, a fault is raised.

Some old alarms had a weaker version of this, where they would dial the security company whenever the door was opened, and then again when the alarm was disarmed. If the second call didn't come in time, the company would instantly know that something was up.

This protected against thieves that would enter the house and smash the alarm before it had time to activate.

> I bet you could examine the keypad for wear. The worn keys (or the shiny ones) are the ones for the code.

That still doesn't give you the order of the key strokes.

But it drastically reduces the number of plausible key strokes, so you might just give your luck a try.

Right. If it's 4 digits, you have 432 combinations. Exhaustive search then works.

If you have 4 unique digits, otherwise it gets even easier.

However, for a 6-digit combination, you'd have to try out 720 combinations in the worst case, so that's already quite a bit less feasible. Although given enough time...

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