Bitcoin Privacy: Theory and Practice - Jonas Nick (Blockstream) - Zürich
Why Bitcoin Stack Exchange recommends it
Bitcoin Stack Exchange answerers point people to it for a concrete look at how blockchain analysis links addresses to wallets and why light client schemes like BIP37 leak privacy.
Recommended by 2 people across 2 different months, 2016 to 2018.
What it is
A 49-minute meetup talk recorded in Zurich in March 2016 where Jonas Nick of Blockstream explains how privacy works and fails on Bitcoin's public blockchain. It covers address clustering heuristics and upcoming technical improvements for privacy.
What people said
Recommends mrkent · 2016-04 · Bitcoin Stack Exchange · on “Bitcoin privacy metrics?”
Here is a great video [this video] in which they asked: given 1 address I know belonging to someone, how many other addresses can I associate with that particular wallet. It turned out to be about 75%. The method detailed in the video uses a few assumptions about how wallets work. Multi-input heuristic : All inputs in a transaction belong to the same wallet. Shadow change heuristic : Change public keys have never been seen before on the blockchain. Consumer change heuristic : Transactions from consumer wallets have 2 or less outputs. Optimal change heuristic : Wallets do not spend unnecessary outputs. This means that a transaction with say 2 inputs of 0.5 each and 2 outputs of 0.6 and 0.4, the 0.
Recommends pebwindkraft · 2018-10 · Bitcoin Stack Exchange · on “How can someone get my private data (such as email, name, IP ...) from bitcoin transaction?”
"If noone listens nodes" - the catch22... Yes, you can define "your" conditions, and you will stay anonymous. Be assured, even when using TOR, there are governmental agencies trying to listen, even setting up "false" TOR systems as exit gates. The way it is done cannot be answered here, and extends scope. But you might want to look at this intro [this video] and do research on bitcointalk.org and google for something like "bitcoin de-anonymization" - tons of links :-)
Cites Pieter Wuille · 2017-01 · Bitcoin Stack Exchange · on “How can a light client be certain he got all relevant transactions?”
It can't. However, it is sufficient to request the information from a single honest peer, as the proof does work in the other direction. This is one of the major drawbacks of using BIP37 [LINK] for learning about transactions (other downsides include terrible privacy [this video] and high load on the servers you're fetching from). Several proposals exist to improve this, including Committed Bloom Filter [LINK] and committed adress-indexed UTXO sets. None of them have been implemented, however.