de0u Just an FYI / update on the use of a google play gift card for anonymity.
You are correct that the process doesn't support using a gift card anonymously. I managed to fudge it (kind of) but still had to give more information than I wanted. The gift card is also only usable for one-off purchases, it can't be used for subscriptions.
Here is detailed info on my experience, in case it helps someone else.
My first few attempts at adding the gift card failed, until it was "locked" and I had to provide "additional information". I don't know whether the lock was due to my age being unverified, giving business contact information, using a VPN, or a combination of the 3.
Age Verification:
Google (unsurprisingly) didn't believe my fake birthday of 1/1/2000 combined with no surname, and they had already downgraded my account to a "child" account with limited privileges. Apparently, in my country you have to be 13 or older to use a gift card (no idea why), so I had to verify my age (no, I don't live in the UK). The frustrating thing here is that at no point while trying to register the gift card did I get informed that my unverified age was an issue, I only discovered this after the gift card was locked.
In order to verify my age, my options were to upload an ID, upload a credit card, or use the PrivacyID webservice. I opted for the 3rd of those, which involves taking a selfie.
Contact information:
Google insisted on having an address and phone number before approving the gift card. I entered the address and phone number of our national Data Protection and Information Commissioner.
Perfect Hindsight:
1) Google now knows who my ISP is - switching off my VPN was my first move when registering the gift card failed.
Lesson learned: Do this while connected to a public wifi somewhere far from home (but still in the country your google account is registered for).
2) I updated my fake birthday to something closer to my real birthday when I read that they would be using a selfie to check my age. Afterwards, I read that Privacy ID claims that they simply advise whether or not you are age 18 or older, so this was probably unnecessary.
Lesson learned: Use a less obvious fake birthday than 1/1/2000 but otherwise, it should be fine as long as it determines an age above 18.
3) Google might have a photo of me - Privacy ID swears blindly the photo stays local but, again, who knows. The risk is higher here than was necessary because I had already downloaded and used chrome to verify my age on my main profile before you suggested switching off JIT in Vanadium. The JIT tip worked for my private space though, so thanks.
Lesson learned: Use Vanadium with JIT disabled for privacyid.com
4) Google now knows the municipality I live in. In order to unlock the gift card, I had to provide a copy of the purchase receipt, which showed the purchase location, which is very near my house.
Lesson learned: Buy the gift card in a shop far from your actual house.
Idea: Use a shop and public wifi that are both close to the business contact information that you provide, so that everything is nice and consistent.
Reading the above makes me feel rather stupid. Clearly, OpSec is not my strength. However, if it helps someone else who genuinely needs to be anonymous, it was worth it ;)