schklom
Roughly speaking, a device will be considered secure if:
- The bootloader is locked and Verified Boot reports a good (green) state.
- The OS is signed with trusted production keys (for example: stock Pixel images signed by Google, or official GrapheneOS builds signed by the GrapheneOS keys).
- The system is on a recent security patch level and not obviously abandoned.
- There is no root, no test-keys, no engineering build, and no obvious tampering like userdebug builds or public signing keys.
- We can verify all of this via hardware-backed key attestation and pin the corresponding OS/boot keys.
In practice that means:
Official stock Pixel and official GrapheneOS builds that meet the above will be shown as secure.
Custom GrapheneOS builds, other custom ROMs (e.g. e/OS), non-public/private builds, or anything signed with public test-keys will not be treated as “secure” in the UI. That doesn’t mean they’re automatically bad, it just means we can’t reliably verify their security properties or update policy, so they won’t get the same high-assurance rating.
The exact list of trusted keys / configurations will be documented, but the core idea is: locked bootloader, verified boot, current security patches, and OS images signed by keys we explicitly trust, without root or dev/test builds.