Day: February 14, 2025

This Week In Security: The UK Wants Your ICloud, Libarchive Wasn’t Ready, And AWS

February 14, 2025 by 11 Comments

There’s a constant tension between governments looking for easier ways to catch criminals, companies looking to actually protect their users’ privacy, and individuals who just want their data to be truly private. The UK government has issued an order that threatens to drastically change this landscape, at least when it comes to Apple’s iCloud backups. The order was issued in secret, and instructed Apple to provide a capability for the UK officials to access iCloud backups that use the Advanced Data Protection (ADP) system. ADP is Apple’s relatively new end-to-end encryption scheme that users can opt-into to make their backups more secure. The key feature here is that with ADP turned on, Apple themselves don’t have access to decrypted user data.

If this order wasn’t onerous enough, it seems to explicitly include all ADP-protected data, regardless of the country of origin. This should ring alarm bells. The UK government is attempting to force a US company to add an encryption backdoor to give them access to US customer data. Cryptographer [Matthew Green] has thoughts on this situation. One of the slightly conspiratorial theories he entertains is that portions of the US government are quietly encouraging this new order because the UK has weaker protections against unreasonable search and seizure of data. The implication here is that those elements in the US would use this newfound UK data access capability to sidestep Fourth Amendment protections of citizens’ data. This doesn’t seem like much of a stretch.

[Matthew] does have a couple of suggestions. The first is passing laws that would make it illegal for a US company to add backdoors to their systems, specifically at the request of foreign nations. We’ve seen first-hand how such backdoors can backfire once accessed by less-friendly forces. In an ironic turn of fate, US agencies have even started recommending that users use end-to-end encrypted services to be safe against such backdoors. Technically, if this capability is added, the only recourse will be to disable iCloud backups altogether. Thankfully Apple has pushed back rather forcefully against this order, threatening to simply turn off ADP for UK users, rather than backdoor the rest of the world. Either way, it’s a scary bit of overreach.

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Lathe And Laser Team Up To Make Cutting Gear Teeth Easier

February 14, 2025 by 23 Comments

Fair warning: watching this hybrid manufacturing method for gear teeth may result in an uncontrollable urge to buy a fiber laser cutter. Hackaday isn’t responsible for any financial difficulties that may result.

With that out of the way, this is an interesting look into how traditional machining and desktop manufacturing methods can combine to make parts easier than either method alone. The part that [Paul] is trying to make is called a Hirth coupling, a term that you might not be familiar with (we weren’t) but you’ve likely seen and used. They’re essentially flat surfaces with gear teeth cut into them allowing the two halves of the coupling to nest together and lock firmly in a variety of relative radial positions. They’re commonly used on camera gear like tripods for adjustable control handles and tilt heads, in which case they’re called rosettes.

To make his rosettes, [Paul] started with a block of aluminum on the lathe, where the basic cylindrical shape of the coupling was created. At this point, forming the teeth in the face of each coupling half with traditional machining methods would have been tricky, either using a dividing head on a milling machine or letting a CNC mill have at it. Instead, he fixtured each half of the coupling to the bed of his 100 W fiber laser cutter to cut the teeth. The resulting teeth would probably not be suitable for power transmission; the surface finish was a bit rough, and the tooth gullet was a little too rounded. But for a rosette, this was perfectly acceptable, and probably a lot faster to produce than the alternative.

In case you’re curious as to what [Paul] needs these joints for, it’s a tablet stand for his exercise machine. Sound familiar? That’s because we recently covered his attempts to beef up 3D prints with a metal endoskeleton for the same project.

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3D Printed Air Raid Siren Sounds Just Like The Real Thing

February 14, 2025 by 10 Comments

Air raid sirens have an important job to do, and have been a critical piece of public safety infrastructure in times of geopolitical turmoil. They sound quite unlike anything else, by virtue of their mechanical method of generating an extremely loud sound output. They’re actually remarkably simple to build yourself, as [MarkMakies] demonstrates.

[Mark’s] build relies almost entirely on 3D printed components and ex-RC gear. The sound itself is generated by a rotor which spins inside a stator. Each is designed with special slots, such that as the rotor turns at speed, it creates spikes of air pressure that generate a loud wail. The rotor and stator are fitted inside a housing with a horn for output, which helps direct and amplify the sound further.

To spin the rotor, [Mark] used a powerful brushless motor controlled by a common hobby speed controller. The actual speed is determined by a potentiometer, which generates pulses to command the speed controller via a simple 555 circuit. By ramping the speed of the motor up and down, it’s possible to vary the pitch of the siren as is often done with real air raid sirens. This action could be entirely automated if so desired.

If you do decide to build such a siren, just be wary about how you use it. There’s no need to go around agitating the townsfolk absent an actual air raid. It’s worth noting that sirens of this type aren’t just used for air raids, either. They’re often used for tornado warnings, too, such as in Dallas, for example. But why not for music?

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