|
| jstrieb wrote:
| I stumbled on this page after reading Matt Blaze's legendary
| paper about deducing master keys from physically strong, but
| cryptographically weak, physical systems.
|
| The paper is really good, and worth a read, even though it is
| from 2003:
|
| https://www.mattblaze.org/papers/mk.pdf
|
| https://news.ycombinator.com/item?id=32306328
| Animats wrote:
| Yes.
|
| There are master keyed systems that don't have that
| combinatoric weakness. Here's the Lock Picking Lawyer
| disassembling a prison lock where there's a separate "master
| ring" for the master key. So combining settings from the master
| key and the operating key will not open the lock.
|
| This lock was opened with a wave rake, though, so it's not very
| good.
|
| [1] https://youtu.be/dleQ_bcbMJo?t=159
| mauvehaus wrote:
| The Bramah lock is interesting for another couple of reasons. I
| haven't taken one apart, (despite being tempted, read on), but
| they're an interesting installation.
|
| A couple years back, I built a custom jewelry box for a customer
| who supplied a Bramah box lock for the job.
|
| Locks for boxes are a perpetual source of hassle in sourcing. The
| thing to realize about a box lock is that rather than preventing
| a shearing motion along the key way axis (like a door or drawer
| lock), they instead prevent you from making a pulling motion away
| from the keyway axis. This is comparatively uncommon (apart from
| patio doors, which are not furniture-sized and are rarely nice).
|
| As a consequence, your options for a box lock are limited.
| Basically everything that's actually available on the market
| apart from Bramah is a warded lock. They are not particularly
| secure, though you can get nicely enough made ones.
|
| Box locks are typically half-mortise, meaning you can see the
| back of the lock from the inside of the box. If that doesn't make
| sense, consider a standard door lock. Those are full-mortise,
| meaning that the body of the lock is entirely contained by wood
| on both sides of the door.
|
| When you install half-mortise lock, you cut the mortise for the
| lock body, fit the lock into the mortise from the back, and give
| it a little bump to make an impression for where the pin the key
| fits over goes. Then you can drill through from the back side,
| cut out the keyhole, and usually also fit an escutcheon over (or
| into depending on the type of the escutcheon) the key hole. They
| key thing here is that you can get your lock nicely fitted and
| flush in its mortise and then drill the hole last. You have
| opportunities to double-check and adjust the fitment of the lock
| as you go before drilling through to the show surface.
|
| With a Bramah, everything is backwards. You drill a hole from the
| show surface for the cylinder, and then you mark out and cut the
| mortise afterwards. If you've left the top of the lock a hair
| proud of the surface of the box, you're shit out of luck. You get
| one shot to drill that hole and drill it _perfectly_ or you 've
| spoiled the show surface. Usually after considerable effort to
| get to the point where you're ready to install a lock. Among
| other things, you've typically gotten to the point where you have
| hinges installed. Which in turn means the whole box is together.
|
| It goes without saying that a test installation or two is highly
| recommended.
| Animats wrote:
| (2005)
| dang wrote:
| Added. Thanks!
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