I know very well about Zerodium. However, FPGAs can be way more secure than any kind of ASICs. If you don't understand why, then I don't think further discussion is warranted. I worked with Apple's implementation of security enclaves, and they don't isolate (or "outsource" to be processed there) nearly as much as should be isolated. For example, whole display and touch input needs to go through the application processor, anyway. It's not a good way to go, to say the least. You can't overlay anything on the top of the display nor isolate touch input from some area (say, virtual keyboard) to go to the enclave. The rest of what it does is pretty meaningless, given these constraints.

Ah, you mean social engineering attacks and more powerful attacks relying completely outside of the cyberspace (to say more bluntly, which perfectly fits the case here, "in the meatspace"), right?

In terms of broadly-understood virtualization, there's always FPGA with its possibility to spawn multiple number of completely independent softcores. These days some FPGAs with enough computing power for well-optimized security-critical part of general-purpose computing (messaging, web browsing, maybe DSP - not computation like neural models) have fully open-source bitstream synthesis tools.

BTW, thanks a ton for letting me know about the unpatched vulnerability in Alpine. I'll talk to the pmOS guys about patching it.

My phone doesn't run Xen yet (I've ran into some problems with kexec() support in Linux on aarch64), but it runs KVM just fine ;)

However, it seems that in Debian it's patched https://security-tracker.debian.org/tracker/CVE-2015-0235 . Is what you're talking about Alpine-specific?

Anyway, Alpine seem to use musl instead of glibc.

https://github.com/positive-security/find-you

"A modified version of OpenHaystack to showcase the possibility of building a stealth AirTag clone that bypasses all of Apple's tracking protection features."

Other projects from them, like https://github.com/positive-security/send-my , also seem interesting.

I absolutely agree with the rest, though, including the part saying any "serious" software will have such features (and better support in general), and I second the examples you gave.

BTW, an interesting thing is that some/most carriers allow you to use CSD/HSCSD over 3G these days, and you can establish data CSD connection between two phone numbers, yielding essentially a dedicated L2 pipe which isn't routed over internet. Can have much lower latency and jitter if that's what you need. Some specialized telemetry is still using that, however as 3G is slowly getting phased out, it will probably have to change.

Everything which can fit into a pocket and has a HTML5 browser?

FYI, I know about how extremely vulnerable average cellular baseband is (and that it would often use unprotected or weakly protected DMA). Let's assume the device in question doesn't have one of these.