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1. Bernie (codewiz@mstdn.io)'s status on Sunday, 10-Oct-2021 18:17:17 UTC Bernie

   Yesterday I found a fascinating gate along my hiking trail: simple mechanical engineering that mimics advanced #cryptography.

   Let's say 4 different officers want to share the ability to unlock this gate independently, but they don't want to use a shared key for some security reasons. For example, they might want to quickly disable or replace one of the 4 keys in case its owner gets fired or leaks it.

   How can they achieve this using common padlocks and iron moving parts?

   • Bernie (codewiz@mstdn.io)'s status on Sunday, 10-Oct-2021 18:23:08 UTC Bernie

     in reply to

     And this is the mechanism. Can you guess how it works?

     Hint: the iron disc carrying the locks can rotate, and the handle on the right can be lifted up.

   • Preston Maness ☭ (aspensmonster@mastodon.technology)'s status on Sunday, 10-Oct-2021 18:26:12 UTC Preston Maness ☭

     in reply to

     @codewiz They make a linked list of padlocks, of course.

   • Bernie (codewiz@mstdn.io)'s status on Sunday, 10-Oct-2021 18:26:12 UTC Bernie

     in reply to

     • Preston Maness ☭

     @aspensmonster Ah! That's how you get locked data structures! 😂

   • kaia (kaia@shitposter.club)'s status on Sunday, 10-Oct-2021 18:27:31 UTC kaia

     in reply to
     @codewiz
     isn't stuff like this quite common? I saw it on radio towers and electrical buildings here
   • Bernie (codewiz@mstdn.io)'s status on Sunday, 10-Oct-2021 18:27:31 UTC Bernie

     in reply to

     • kaia

     @kaia Don't you need to open all 4 locks to open this one?

   • Bernie (codewiz@mstdn.io)'s status on Sunday, 10-Oct-2021 18:29:57 UTC Bernie

     in reply to

     • kaia

     @kaia Oh, I see... removing one peg creates enough slack to slide the latch out of its keeper...

   • Bernie (codewiz@mstdn.io)'s status on Sunday, 10-Oct-2021 18:35:35 UTC Bernie

     in reply to

     • kaia

     @kaia But the linear design seems simpler...

     Perhaps the circular padlock carousel is more tamper resistant? No... I would just cut off or bend the peg...

   • kaia (kaia@shitposter.club)'s status on Sunday, 10-Oct-2021 18:35:37 UTC kaia

     in reply to
     @codewiz
     yeah, the one you posted is nicer though :comf:
   • Fabimaru (fabimaru@framapiaf.org)'s status on Sunday, 10-Oct-2021 21:04:48 UTC Fabimaru

     in reply to

     • kaia

     @codewiz @kaia It could be possible to create a design inspired from this one that would require removing N locks out of X to allow a latch to slide.

   • Bernie (codewiz@mstdn.io)'s status on Sunday, 10-Oct-2021 21:05:20 UTC Bernie

     in reply to

     • Fabimaru
     • kaia

     @Fabimaru @kaia Multisig!

   • Bernie (codewiz@mstdn.io)'s status on Monday, 11-Oct-2021 07:20:25 UTC Bernie

     in reply to

     • Patrick Georgi

     @patrick Correct! 🎉

   • Patrick Georgi (patrick@georgi.family)'s status on Monday, 11-Oct-2021 07:20:26 UTC Patrick Georgi

     in reply to
     @codewiz So you unlock your own padlock, rotate the disk so its hole lines up with the handle's metal rod, and then you can pull up the handle because the rod passes through the now-freed-up hole?
     
     It's certainly a very interesting approach, thanks for sharing!
   • Bernie (codewiz@mstdn.io)'s status on Tuesday, 12-Oct-2021 06:24:02 UTC Bernie

     in reply to

     • Patrizio

     @Izio I knew a few people called Patrizio, but your profile doesn't give away a lot in terms of hints.

     Have we been coworkers? Have we been together in the "servizio di leva"?

     Anyway, welcome to Mastodon!

   • Patrizio (izio@mastodon.bida.im)'s status on Tuesday, 12-Oct-2021 06:24:04 UTC Patrizio

     in reply to

     @codewiz

     Ciao Bernie, very long time no see, maybe you don't even remember who Patrizio is... 😀
     However, I understand the mechanism of gate, but I'm curious.. and cannot arcive how the hypothetical 3 remaining authorized owners can "disable" the fourth owner'lock who is no longer authorized (without him returning key lock). I mean a clean way, not cutting lock with large wire cutters!