The title is misleading.
App attestation does not require an Apple account nor a google account. For Android, it does limit the ROMs to Google certified ones and requires GMS to be installed if Play Integrity is used. An alternative option, would be to use the Hardware Attestation API directly, GrapheneOS would be thanking you.
I've spent a good amount of time implementing exactly this type of system for a backup service.
his document specifies a way to cryptographically attest the integrity of a HTTP request hitting a server.
The attestation proves the request came from a device and attest the legitimacy of the bootloader, OS and app.
Google and Apple are in a privileged position to be able to bypass the app attestation though, so depending on the threat model, it's not bulletproof.
edit: Play Integrity could the worst offender here, as it can be leveraged to force a user to have installed the app through the Play Store. Indirectly, requiring a Google account.
> App attestation does not require an Apple account nor a google account. For Android, it does limit the ROMs to Google certified ones and requires GMS to be installed.
To me, there is no difference between your sentences. You require the blessing of an American company to be able use eIDAS. Google has the power to disable eIDAS at a national scale by making the attestation services treat all devices as not certified.
There should be NO reliance whatsoever on a private company not under the control (direct or indirect) of the government let alone a foreign private company.
Edit: I just noticed your username and the fact that your account is very new. Are you astroturfing?
There's no such thing as "legitimacy of the bootloader, OS" that can be verified by someone who isn't the device's user. The bootloader that booted the phone I type this on is patched by me, which makes it more "legitimate" than any other bootloader that could be placed there.