Schneier on Security

Clive Robinson • February 18, 2010 11:48 AM

Foil impresioning is just one of many ways.

When I was young I realised you could impression a (mortice) lock with engineres blue ot just plain chalk dust.

All mechanical locks can be impressioned in one way or another with time and patience. The trick as pointed out by cybergibbons is working out how to stop other parts of the lock masking the little tell tales you are looking for.

Impressioning is one of the reasons the lock industry has been stuck in a rut for the last god knows how long.

Locksmiths don’t want to ruin what they have, their little trade secrets etc. And the mystique of “trade secrets” actually holds them back in that they tend to defere (belive) “a master” without question when told something “cannot be done” rather than find out “it can” for themselves.

Mat Blaze (www.crypto.com) has had some interesting run ins with “Brotherhood” in the past.

I’m of the opinion that a curious child can be entertained for hours by being shown how to do basic lockpicking and is actually less likely to use it for “naughtyness”.

I know when I was younger teachers etc came to accept the fact that I could “open doors that others could not” rather than wait for the key. Ultimatly even a Headmaster came to realise it was usefull (when he locked himself out of his office 😉

I guess the real reason I never turned to crime is I’m just to easily recognisable (@ BF Skinner – that does not mean I do actually look like what you think 😉

Clive Robinson • February 20, 2010 6:07 PM

@ Rick Damiani,

“That this lock requires a collection of special tools, preparation, and time to overcome means that it’s doing it’s part to slow down unauthorized access”

Barely.

Let me put it this way, you buy a lock for several reasons two of which are,
1, As a general deterant.
2, As a method of reducing insurance premiums.

Both are designed to make a naredowell go to a softer target etc.

If I walk up to your door today and briefly press a little putty against the lock whilst apearing to ring the bell, then wait a little while then walk off.

I have an impresion of the lock face and key way. At home I look up the makers name ad the keyway profile and get a blank (fairly easy to do).

I make up the foil key in this evening it takes maybe twenty five minutes.

Tomorrow I park up oposit your place and wait for you your loved ones etc to go out.

I go across to your door and again pretend to ring your bell whils working the foil key.

Your door opens after a few minutes.

One of two things is going to happen.

1, It goes wrong for me in some way lets say that the burgler alarm starts it’s countdown or a dog starts barking or I hear somebody in your house. In which case I step back outside pull the door to and go away.

2, I walk in and search around and selectivly take only a couple of items that are not immediatly obvious they have gone and I leave.

You come back,

If 1 has happened you put the alarm down to an accidental trigger.

If 2 you spend the rest of tomorow in your house being none the wiser.

Either way with high probability you’ll be moving around doing your thing and destroying any eveidence of my physical prescence.

Let’s say I did take a couple of items and a few days from now you discover one of the items is missing.

Who are you going to blaim me or a member of your family or friends etc.

Whilst not a perfect crime I could if I was carefull how I fenced things do a house or two a day virtually any day of the week I chose for a very long time. I could after a few months come back to visit you again…

Locks alone are not enough of a deterant these days you need to back them up not just with alarms but covert CCTV these days.