There are some really exciting Android security projects out there... For instance, one awesome function a-la-Truecrypt involves full disk encryption with plausible deniability. You are able to give out a first-layer passphrase if you are coerced - yet a truly private volume remains secure and disguised within the apparent unused portion of the storage disk.
Yet it's unlikely that any of this is relevant to you, otherwise you wouldn't be asking this sort of thing. When it comes to security leaks, try to barricade off the paths of least resistance from the ground up. For instance, even all of that wouldn't do much good if you had forensic evidence of your phone config on your computer, a lockscreen that could be bypassed, a phone seized whilst still turned with encryptions keys remaining in RAM, etc. Also keep in mind all of the data you are sending out in the clear via your cloud storage, SMS/IM, WiFi, etc.
So in the end, just pick a ROM that runs smoothly and you enjoy. Whatever you end up deciding, make absolutely certain to:
- encrypt with strong passphrase (then use cryptfs app to create a shorter lock screen key)
- disable USB debugging
---------- Post added at 06:06 AM ---------- Previous post was at 05:32 AM ----------
Originally Posted by JamieFL
How do you get your own private key and what does that do? Sorry, I have never heard of this, so I'm sure others are probably also wondering.
Sent from my Nexus 5 using XDA Premium 4 mobile app
This probably isn't exactly spot on, but here's a rough sysnopsis... When a ROM is built from source, the creator "signs" their creation (i.e. the ROM and the apps within). This way you can be sure that you're indeed getting an official ROM built by AOKP (or whomever) and not by some malicious 3rd party. Likewise, the Android OS uses signatures to ID which files are legitimate and given permission to run (i.e. official updates). However, there have been incidents with custom ROMs when this functionality has been exploited. This could allow an otherwise innocuous seeming app to deploy hidden malware and cloak itself as a legitimate app, gaining full rights to the phone.
A self-built ROM with your own private key is presumably safer against such an attack. I don't think most people would need to be concerned about this, but still something to keep in mind. Unfortunately jcase is spot on about custom ROMs almost always creating or exposing more vulnerabilities than stock. For instance, features like ADB or USB-OTG are often enabled by default. If that wasn't bad enough, in the event that your phone is ever lost/stolen/seized, having a custom recovery installed is pretty much handing over your identity with a bow wrapped on top. It makes it easy for anyone to bypass PIN/password/face/gesture-lock or dump off the entire disk image. Not to mention analysis can reveal your account passwords, WiFi keys, SMS, phone records, photos. Most of these vulnerabilities can be safeguarded against with careful consideration, but you certainly won't get there by default.