Bitcoin is a digital currency and electronic payment system operating over a peer-to-peer network on the Internet. One of its most important properties is, theoretically, the high level of anonymity it provides for its users. A lot of people think that.
The only problem is it's possible for any people knowing mathematics and with enough funds to spend to set up live servers to localize BTC address and reveal the IP and the Geolocalization.
And Old study remember us that with some maths, BTC has nothing to do with anonymity and you can bet that government agencies and/or others actors have dozens of thousand of servers tracking the exact flow of money behind #BTC
Even if the study is 6 years old, the study shows a clear path of how Bitcoin suffers of lack of anonymity :
By the way, there were many changes inside the Bitcoin core since 2013...Ok...but there are still problems on board now in 2019.
First, the majority of people are holding assets on a web based wallet.
They don't have a copy of the blockchain locally then they connect to a website where their IP is automatically stocked by the exchange server, the broker or whatever.
In many countries, there is an obligation to keep the log active for many years and then anybody can link easily your wallet to your IP.
If you connected one time outside any good VPN, you have a direct link between your wallet and your IP then you, forget anonymous stuff.
a P2P philosophy needs a P2P architecture. For the moment we are driving fast to a centralized information system around Crypto then finally something which is killing a part of the spirit of the beginning.
I don't speak about people putting their BTC address on website to be paid, printed the QR code of the BTC in flyers or others stuff that definitively put their money publically shown.
People interested in security and Bitcoin can find a lot of information here :
Where you will be able to go deep in the subject and it's perhaps where, outside any click-like title on blog posts, you can find useful information on how to protect your privacy.
And i recommend a very good blog post about the subject here :
Be safe, stay informed !