The best airgapped OS for mobile wallet

[Oshosondy]

I like one thing about computer, you can decide to choose either Windows or Linux, I do not know if Windows is open source but Linux is open source, Linux is commonly used by experts that have known about malware, people that are not using it are many, this make this OS the best to have wallet hackers like what plenty people are using, it is open source. Having airgapped wallet on such OS device is excellent, it is even good for having online wallet like electrum on the device Linux OS.

I want to know about phones, all I know about Android is that no other OS can run on the Android devices but only Android OS, I do not like Android because the ads that are popping up is tiring, ordinary scrolling your phone up will bring up ads, it is not good as a mobile wallet, but my question is still different, is it good to have airgapped wallet on Android which is not open source? Is there alternatives for Android just like Linux is an alternative to Windows?

[mocacinno]

Well... Theoretically, android is open source aswell... It uses the linux kernel and the source code is open: https://cs.android.com/android/platform/superproject/

There are usually alternative ROM's available to flash your cellphone, but to tell you the truth: if you don't know the guy that built the rom personally, you're probably worse off than using the ROM provided by your vendor...
I mean, the odds of samsung or oppo or xiaomi stealing your funds trough a backdoor in their official ROM are smaller than the ROM build by HaCkErBoY_LoVeS_BrOnYs_2012

For an airgapped setup, theoretically it shouldn't matter all that much... As long as you stick with the ROM provided via the official channels AND you use a peer-reviewed, trusted, popuplar waller, AND  you check the signature of the wallet you're going to use to setup an airgapped setup, you should be fine with protection against remote attacks (because, well, that's the defenition of an airgapped setup: no network connectivity = no remote attacks... )

I mean, airgapped means that even if there are vulnerability's in the OS, it shouldn't matter all that much, unless somebody has physical access to the cellphone itself and the vulnerability lays in the encryption, authentication or access controll. But yeah, that's the same with any airgapped setup: it's very (VERY) secure as long as the attacker has no physical access to your device. As soon as the attacker has access, sure, there's a difference between different kinds of hardware (a cellphone is easyer to steal than a laptop, which is easyer to steal than a desktop, which is easyer to steal than a rackmounted server) and there's a difference between OS's (and the versions of said os), and also with different kinds of setups within the same OS (for example, running your airgapped wallet on a luks encrypted partition on a recent linux distro that was recently patched offline and uses reasonably strong authentication, without any non-essential binaries installed is much safer than running an airgapped windows XP that is also used to run a dozen of cracked games).

[NotATether]

There is no such OS for phones. The mainstream mobile OSes phone home (no pun intended) to run some of their background tasks. Just turn off WiFi, cellular and Bluetooth and you got yourself an airgapped phone. You're at least lucky that it's way easier to shut off networking than on Windows or macOS.

[o_e_l_e_o]

If you have very serious concern, consider CalyxOS & GrapheneOS. But it's only available on very few smartphone.

Both Calyx and Graphene mostly only support Pixel phones. There is also LineageOS - https://www.lineageos.org/ - which supports a much wider range of devices, including most phones from LG, Sony, Samsung, Motorola, and many others. You can see their full list of devices here - https://wiki.lineageos.org/devices/.

There are usually alternative ROM's available to flash your cellphone, but to tell you the truth: if you don't know the guy that built the rom personally, you're probably worse off than using the ROM provided by your vendor...
I mean, the odds of samsung or oppo or xiaomi stealing your funds trough a backdoor in their official ROM are smaller than the ROM build by HaCkErBoY_LoVeS_BrOnYs_2012

I think you are doing a bit of a disservice to some of these open source alternative OSs. Lineage, for example, has been around for years, has hundreds of contributors, and has a community of hundreds of thousands of users. They have a very active GitHub and Gerrit, a busy subreddit, and an extensive wiki. It is a far cry from a one-man-project by some random internet denizen.

[mocacinno]

@o_e_l_e_o: to tell you the truth, i used to buy more "unknown" brands in the past, and when i looked for alternative ROM's, the only choiches i had that supported my models were always one-man-shows... I even flashed my phone with some of them since those unknown chinese brands had the nasty habit of not releasing any patches, and after a while you could either use a phone that didn't receive patches for a couple of years or you could roll the dices with an unofficial one-man ROM.

Needless to say, i did not use my phone for banking (either FIAT or crypto) after i flashed it with some uknown ROM, nor for anything else that could have been considered to be important... Just some calling, texting and general surfing.

It's possible there are better alternative OS's out there, i just have 0 experience with them... I buy more known brands nowadays, but it's on my employer's dime (they give me money to buy a cellphone), but they also have rules against running unofficial firmware on any device they pay for.

So, in short, i might have generalised a little bit... Maybe there are more qualitative firmwares out there... I still wouldn't give them the same level of trust as an official ROM from a big company... Imagine the sh*tstorm they'd have to go trough if somebody lost actual money because of an intentional backdoor built into their official ROM... But still, there might be some decent projects out there that are more or less trustworthy (i still don't think they'd face the same consequences if word got out they had an intentional vulerability tough).

[kaggie]

SailfishOS is pretty good, and a decent compromise between usability (it has whatsapp and facebook) and security (programmes can be isolated).

You can also get Ubuntu on your phone, which works ok as a phone, but not as well with the other things phones are connected with these days.

I've never tried a wallet on any phone though..

[The Sceptical Chymist]

I mean, the odds of samsung or oppo or xiaomi stealing your funds trough a backdoor in their official ROM are smaller than the ROM build by HaCkErBoY_LoVeS_BrOnYs_2012

Lol, seriously--and especially for people like me who don't have the know-how to evaluate whether a phone's code contains anything malicious.  I would definitely trust an OS like Android's not to steal anything from me over somebody's homebrew OS (though I like the idea of the latter).

Aside from that, though, I wouldn't recommend keeping any crypto on your phone.  Even if you have your wallet backed up, there's always a chance (to the best of my knowledge) that it can be hacked if someone gets their hands on it.  And heaven forbid the cops should seize your phone for any reason--and believe me, they will do so if they can find any reason to--you'll be giving them way more information about your crypto habits than they need to know about.  Hopefully none of you have to experience either one of those situations, but my point is that it's really not a great idea to walk around with your bitcoin/crypto wallet(s).

[PrivacyG]

Something is conflicting or confusing in your post.  Specifically, it is that you are looking for an airgapped OS according to the title but for an airgapped wallet according to the text.  Either way, a mobile phone is a bad choice if you are looking for an airgapped device.

For airgapping, you could use an old PC of yours.  Disconnect all wireless modules if there are any, wipe the disk, encrypt it and install a safe Linux distro.  Mobile phones are bad as airgapped devices unless you keep and only use them inside a Faraday room you most likely do not have.  Considering most if not all Smartphones have non-removable batteries, wireless modules and so on, your wallet will never be completely airgapped.

If you are still tempted to purchase a Smartphone for cryptocurrency storage, I recommend you to either flash an official, reputable custom ROM such as Graphene, Replicant or Lineage or use the default ROM.  Undoubtedly, there are drawbacks in both choices.  The Custom ROMs I just mentioned are Google-free which provide a great improvement privacy-wise.  But the bigger disadvantage is that Custom ROMs in fact sometimes have a weaker security than default ROMs.

There are specific viruses that only bypass your device's security in certain conditions.  To give an example, there are viruses that target rooted devices.  Smartphone users who flash Custom ROMs sometimes prefer to keep their Smartphone rooted for an often false feeling of being under control.

An alternative to Android would be either iOS or a Purism phone.  The Purism phone runs Manjaro as far as I know, which is a very popular Linux distro although it is not fully free unlike vanilla Debian for instance, which I definitely do not like.  On the other hand however, Librem's phone supposedly has a physical module switch and I reckon the switches are for cellular, wireless, microphones and cameras.  How legit these physical switches are is out of my reach for now however.

If the switches are legit, I would imagine it is possible to airgap their phone and even run about any cryptocurrency software since it is a Linux distro that is running on it.  As previously stated, there are drawbacks in pretty much anything you may want to choose.  Depending on the level of paranoia you have about these devices, you have a rather wide variety of choices to pick from.

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Regards,
PrivacyG