Use a strong authentification method

See #password

Stop using google pay

Google pay is the worst privacy mistake, you give a ll of your financial data to google.

As a replacement you can just use your credit card in your phone case.

Stop using SMS

SMS is inerently unsecure and... being only usable using google message app it shouldn't be trusted either.

The alternative is to use a secure encrypted messaging app such as Signal, Threema or Simplex.

While WhatsApp does encrypt messages it collect and store a lot of metadata and as such shouldn't be trusted either.

Install GrapheneOS

Graphene OS is an alternative operating system for your mobile. It is fully degoogled but because of it's security prerequiesites it needs to be installed on a Pixel phone (preferably one post pixel 8 for better memory safety).

Installing Graphene OS is really easy and can be done in your browser in less than an hour without any risk of breaking your device.

Here is a great guide on how to get started using Grapheneos.

Do not use your phone number to register accounts

You shouldn't use your phone number for anything else than as an id to contact you trought secure messaging apps for the persons you know.

For any account or untrusted party you should use temporary phone numbers.

Purchase SIM cards anonymously

You can use either a prepaid sim card paid for in cash or a sim card from services like SilentLink.

It is important however to understand that this sim card will have your phone informations and be able to track your movements.

Stop using google services

This one is pretty straightforward, if you want privacy from google then you should stop using their services. Most have better alternatives anyway.

Disable Face Unlock and Biometrics

If your threat models consider governments, criminals or... as threats then you should prevent any authentification method that could be used without your consent. This includes authentification methods based on the principle of what you are or what you have access to. In that specific case, you should prioritate the methods that use what you know.

Use a SIM mobile router

If you do not want your phone to be registered with a sim card but still want to have the 4/5G capabilities you can use a mobile router that accepts a sim card.

This will not block location tracking of the sim card or traffic analysis however.

Stop using a sim card completely

A phone is basically a computer now. If you do not need instantaneus notificatios you can use it without a sim card trought wifi only.

This would protect you agaisnt an adversary using a Cell Site Simulator to locate you and/or read your traffic Talk about CSS.

Use a voice changer

If you are concerned about your voice being recognized or analyzed, you can use a voice changer app to modify your voice during phone calls. Be warned that any change you make to your voice can probably be reversed trought forensic analysis (even trought some countries stopped the use of forensic voice science in court due to reliability concerns). Consider this depending on your threat model.