To be more precise, 4 of the 16 german states use it already (of course Bavaria one of the 4). Others are planning to test it and also federal police was probing it but this has been denied by the ministry so far and in many other states there is a lot of opposition to it. So the fight to data sovereignty and privacy continues. Also in 2018 the German supreme court set up high legal barrier to “automated data analysis” which makes it difficult to fully use Plantirs capabilities. You see a detailed analysis of the whole situation in Germany by CCC here: https://media.ccc.de/v/39c3-blackbox-palantir#t=1621

not all heroes wear capes

There definitely an actively developped open source privacy focused period tracker available, go check it out: https://gitlab.com/bloodyhealth/drip But all data stays local on your device , which is of course good from privacy pov but if you are looking for something accessible from different devices then this might not be suitable.

The amount of trolls in this thread that either try to spew false information intentionally or just have no idea what they are talking about is insane.

If you are worried about what data (including your phone number) law enforcement can recieve (if they have your specific user ID, which is not equal to your phone number) from the Signal company check this: https://propertyofthepeople.org/document-detail/?doc-id=21114562 Tldr: It’s the date of registration and last time user was seen online. No other information, Signal just doesn’t have any other and this is by design.

If you want to know more about how they accomplish that feat you can check out the sealed sender feature: https://nerdschalk.com/what-is-sealed-sender-in-signal-and-should-you-enable-it/

or the private contact discovery system: https://signal.org/blog/private-contact-discovery/

Also as Signal only requires a valid phone number for registration you might try some of these methods (not sure if they still work): https://theintercept.com/2024/07/16/signal-app-privacy-phone-number/