Prey solves a slightly different problem. The purpose of device protection isn't to help you recover your device, it's to prevent thieves from benefiting from stealing your device. As such, it will only work if broadly deployed, because we need to build a "herd immunity" effect. There may be some devices that can be stolen usefully, but if most can't thieves will stop targeting Android devices. This is why it's not an app but part of the base operating system.

I'm pretty certain disabling app-disabling would cause the device to fail the compliance test suite. There's a test that's supposed to check that.

The target market for this watch is the people who want to tell the world "I am so rich that I drop $17K every other year on an ugly watch". The comparisons with Rolex, et al, are off the mark as well. Those target people who want to spend an outrageous sum on a beautiful piece of jewelry that will last for decades, if not generations. Apple has recognized that those brands are missing an opportunity, because they build devices that are good for a long time and so don't truly address the market which has as its goal to show the world that money is simply irrelevant.

The $17K Apple Watch is for the nouveau riche who aren't wealthy or famous enough that the world knows they're rich, and feel the need to demonstrate it visibly. The truly wealthy don't need to do this, because everyone recognizes them from Forbes Magazine's annual article on their wealth -- and/or because they aren't insecure people whose self-image is propped up by people bowing and scraping over their money.

Indeed it didn't. Idiots. $10M appeared to do the trick. Though they did apparently take the money and adopt the PRNG before it was realized that it was likely backdoored, and before we realized that the NSA had abandoned their mission to improve US COMSEC.

Assuming there isn't something that prevents the boot image from being replaced. See my other, more extensive, comment in this thread.

Don't be condescending. I'm not saying rebooting is a magic anything.

Whether or not this matters depends on the threat model and why the attacker is interested in patching the kernel. For example, one purpose would be to disable other kernel security features, such as SELinux, or dm-verity. Most SELinux rules are configured and the configuration can be altered by root, but some are compiled into the kernel and can only be modified by modifying the kernel. Altering the persistent kernel image may not be possible for a variety of reasons (read-only media, SecureBoot, etc.). In addition, in security-sensitive and mission-critical contexts an unexpected reboot may well be noticed.

I don't understand your assertion about SecureBoot. Are you referring to some known vulnerability of some particular secure boot system? Given a decent implementation of secure/verified boot, an attacker should not be able to convince the system to boot a modified kernel image, which means that run-time modification of the kernel is the only option if the attacker needs to bypass some kernel security enforcement.

In general, the security model of a high-security Linux system assumes that the kernel is more trustworthy than root. The ability for root to modify the running kernel invalidates this assumption, which most definitely is a security issue.

In the context of a system without mandatory access controls there may not be any reason to care, since once an attacker has obtained root there probably isn't any limit to what he can do.

Sure, if your concern is error, rather than malice. An attacker who gains root could use this to dynamically patch a backdoor into the running kernel. Rebooting the machine would potentially enable someone to notice.

As another poster noted, though, you can already dynamically patch the kernel for malicious purposes by loading a malicious module, assuming that hasn't been disabled. In contexts where security is crucial, I would disable both dynamic module loading and run-time patching.

The GP wasn't suggesting that excessive data was handed over, he said that an NSL could be used to demand installation of a backdoor. If I were a vendor, even one who really wanted to be cooperative, I'd balk at that, because the chances of something like a backdoor being discovered are too high. It would be actively sabotaging my customers, and not just to the NSA... a backdoor can't distinguish between users, it lets in anyone who figures it out. And, of course, if the existence of the backdoor were published it would do serious damage to my business.

Even companies who want to cooperate are going to be reluctant to do potentially business-destroying favors for the government. There would be a great deal of incentive to fall back on the law and refuse on the grounds that the law doesn't authorize such requests.

I'm skeptical that an Android device would survive running flat out for two years to crack a PIN. The heat and battery life issues I experienced when I tested it demonstrate clearly that mobile devices simply aren't designed to run full-speed 24x7.

Also, it should be pointed out that the attack I described is far from easy to carry out. Among other things, it requires dumping the contents of flash, which basically requires removing the flash chips from the mainboard without damaging it, then either putting the flash chips back or installing new flash, then the device must be unlocked, a custom, hostile OS flashed, and finally the attacker can start the multi-year process.

Note that the 630-day figure I cited is on average. It would take twice that long for a guaranteed break.

Finally, if you add one more character to your passcode (7-character alphanumeric), the crack time jumps from 630 days on average to 124 years.

I agree that Lollipop FDE still needs some improvement, but it's already quite good.

Your argument would carry more weight if the government who'd be trying Snowden weren't the same one he outed for violating its own laws, with the active collaboration of its judicial branch. Not to mention all of the recent fully-public sidestepping of due process for hundreds of other enemy combatants. Oh, and the torture, including of US citizens. And... do I really need to go on?

Snowden has extremely good reason to be skeptical of the fairness of a trial... or if he'd even get a real trial.

I see no evidence that Snowden didn't hand everything over to the Guardian et al, all at once, as he said he did. On what do you base your claim that he's still got something left?

In most cases these days it's a distinction without a difference.

I see this differently. Obj-C has the objects I need to interact with the framework. C++ has the speed, compatibility and expressive power I want. C has speed and compatibility, but lacks expressive power, which creates a lot of tedium and loses a lot of safety.

We agree on something :-)

I haven't really done much on Macs, but I did a lot of work on NeXTstep back in the day, and C++ was quite common in scientific computing there. Actually, what I saw a lot of was "Objective-C++"... they may have grown further apart, to the degree that this no longer works, but in the early 90s gcc allowed you to mix Objective-C and C++ constructs freely in the same code. So a common approach was to build everything in an OO fashion, but to choose between Objective-C and C++-style classes based on performance and flexibility tradeoffs. The result required you to be fluent in both, but that really just means being fluent in C++ because a C++ programmer can learn Objective-C in a day (which is something I respect about the language).

Cross-platform compatibility of C++ code is excellent these days, C++ can call low-level Apple APIs exactly as well as C, and there is no performance cost to C++ unless you choose it.

Unless you're concerned that you may need to target a platform not supported by a decent C++ compiler (which is really rare, given that gcc is basically everywhere), the only reason to choose C over C++ is personal preference or concern that some of the users of the code may not know C++.

It's not separate. In stock Lollipop there is only one password, and it's used both for FDE and for screen unlock. Some customized ROMs (e.g. CM) have separated it, which allows you to choose a strong boot password and a more convenient unlock password. Stock Android didn't go that direction because too many users would set a strong boot password which they only use once every few weeks and therefore forget, losing all of their data.