Privacy & security

Almost nobody loses bitcoin to broken cryptography. They lose it to a convincing message, a reused password, a phone number ported onto somebody else's SIM, or an address quietly swapped in a clipboard. This section is the vocabulary of how that actually happens.

The attacks split into two families. Some target you: phishing, SIM swap, address poisoning, and the long confidence scams that end with a fake trading screen showing a balance that was never there. Others target the chain: dusting attacks that tag your coins so they can be followed, chain analysis that follows them, and at the far end a 51 percent attack that rewrites recent history.

Privacy and security are different problems and the terms get mixed up constantly. Coin control and coinjoin are privacy tools; they decide what an observer can learn. Two factor authentication and hardware signing are security tools; they decide who can spend. A perfectly private wallet with a weak password still gets emptied.

Proof of reserves sits between the two, and belongs here rather than under exchanges, because it is a claim you are being asked to verify rather than a product you are being sold. Read it before deciding how much to leave on any platform.