Bitcoin Privacy: Pseudonymity vs. Anonymity

Bitcoin is pseudonymous, not anonymous. No name appears on the blockchain, but every payment is recorded there forever, readable by anyone. Your Bitcoin privacy therefore comes down to one question: does anyone know which addresses are yours? As soon as an exchange, a merchant or a friend knows that at one point, they can follow many of your payments backwards and forwards from there. How far is decided by how you behave.

Pseudonymity and anonymity: the difference

A payment is anonymous when no one can attribute it to a person, nor link two payments by the same person. Cash comes close: the baker sees your face, but the ten-euro note in the till doesn't reveal where you spent money before.

A payment is pseudonymous when it runs under an alias. In Bitcoin, the alias is the address. The catch: everything that ever happened under that alias is public. Once the alias is uncovered, it is uncovered for the whole past and for everything that follows.

Satoshi Nakamoto described this openly in the 2008 white paper. Section 10 compares Bitcoin with the tape of a stock exchange: you can see that someone is sending an amount to someone else, but not who. The same section already names the key weakness: payments with several inputs almost inevitably reveal that those inputs belong to the same owner.

So Bitcoin is both more private and more public than your bank account. More private, because no company has to write your name next to the address. More public, because anyone with internet access can read the payments, not just the bank.

How chain analysis links addresses

Chain analysis means evaluating the blockchain's public payments and grouping addresses that probably belong to one person or company. Firms such as Chainalysis, Elliptic and TRM Labs sell this to exchanges and authorities. The basics are public and surprisingly simple. One of the first major studies appeared in 2013: "A Fistful of Bitcoins" by Sarah Meiklejohn and colleagues at the University of California, San Diego.

Rule of thumb 1: shared inputs belong together

How a Bitcoin payment is assembled from several "notes" (UTXOs) is explained in How does a Bitcoin transaction work?. For privacy, one thing matters: whoever signs a payment with three inputs needs the keys to all three. So they probably belong to one person. This assumption is called the common-input-ownership heuristic. It is the analysts' strongest weapon, because almost every wallet works this way.

Rule of thumb 2: change gives itself away

A payment usually has two outputs: the amount for the recipient and your change. If the analyst works out which output is the change, they can keep following your trail. Clues:

• Round amounts: 0.01 BTC to the merchant, 0.03718244 BTC back. The odd amount is almost always the change.
• Same address type: If you pay from a bc1q address and one output goes to a bc1q address, the other to a 3 address, the bc1q one is probably yours. The formats are covered in Bitcoin addresses explained.
• Reused addresses: If an output goes to an address that has been used before, the other end is usually the recipient.
• Wallet fingerprints: Fee level, order of outputs, version number. Every wallet software has its habits.

Rule of thumb 3: known addresses as anchors

The rules of thumb only link addresses with each other. The name comes from outside: from an exchange's customer records, from an address someone posted in a forum, from a donation appeal, from an invoice. Analysis firms keep lists of millions of such tagged addresses. One hit is enough, and the whole cluster has a name.

Address reuse: the most common mistake you make yourself

Using an address more than once puts your payments openly side by side. How wallets avoid this by themselves is explained in Bitcoin addresses explained. Three cases where it happens anyway:

• Donation address in a profile: A fixed address on your website or social media shows everyone every incoming payment and, as soon as you spend, where it went.
• Savings plan with a fixed withdrawal address: The exchange pays to the same address every month. All your purchases sit visibly together, with your name at the exchange.
• Old wallets: Early wallets and some exchange wallets used a single address for everything.

Fresh addresses help against outsiders, but not against rule of thumb 1. If you later spend all your savings-plan deposits in one payment, that payment links them again.

KYC: where your name gets onto the blockchain

The strongest anchor isn't analysis but buying with ID. Exchanges, brokers and savings-plan apps in the EU and Switzerland must identify their customers and know every address they pay out to and that you deposit from. That links the start of your trail to your name, permanently, in the files of a company that can be hacked or go bust.

Since 2026 there is also reporting to tax authorities: what providers report under DAC8 and CARF is explained in DAC8 and CARF. And for transfers between providers and to your own wallets, the Travel Rule requires name and address to travel along. If you want to buy bitcoin without this anchor altogether, the routes and their legal position are in Buying Bitcoin without KYC.

For privacy this means: bitcoin you bought with ID count as yours for the exchange and the authorities, however often you move them afterwards. You can only influence how much others see: the merchant, the recipient, the curious acquaintance.

CoinJoin: obscuring payments together

CoinJoin is the direct answer to rule of thumb 1. Several people build one joint transaction: each brings their own inputs, and many outputs of exactly equal size are created. Each person signs only their own input; nobody can take the others' coins. From outside, you can't tell which output belongs to which input. The assumption "shared inputs, one owner" is wrong here, and that's the point.

The idea came from Gregory Maxwell in 2013. It became known through two wallets that both suffered a blow in 2024:

• Samourai Wallet: In April 2024, US authorities charged the two founders and seized the servers. The charges: money laundering and operating an unlicensed money-transmitting business. In 2025 the founders pleaded guilty to the second charge only and in November 2025 received prison sentences of five and four years.
• Wasabi Wallet: Its maker zkSNACKs shut down its CoinJoin coordinator on 1 June 2024, citing a lack of legal certainty. The wallet itself still works and can connect to independent coordinators.

As of November 2026, CoinJoin still exists, but through smaller independent coordinators and open-source software, no longer through the large companies of the time.

Lightning, PayJoin and Silent Payments

Not every improvement needs mixing. Three techniques improve privacy when making ordinary payments.

Lightning: private when paying, visible when opening

Payments over the Lightning Network are not recorded on the blockchain. They pass through several nodes, and each hop knows only its predecessor and successor, not sender and recipient. The method is called onion routing, as in the Tor network.

Two gaps remain. First, opening and closing a channel is an ordinary Bitcoin payment. Anyone who sees your exchange withdrawal flowing into a channel knows how much you keep ready for Lightning. Second, with a convenient mobile wallet your Lightning provider often sees whom you pay. And the invoice contains the recipient's node unless they hide it behind detours.

PayJoin: sender and recipient both contribute

In a PayJoin payment (BIP 78), the recipient also contributes an input to the transaction. From outside it looks like an ordinary payment with two inputs. Rule of thumb 1 says "both inputs belong to Anna", and that's wrong. Because PayJoin can't be told apart from normal payments, every single PayJoin weakens the analysis of all other payments too. The catch: sender and recipient both need a wallet that supports it, and in the first version the recipient had to be online. A follow-up (BIP 77) allows the exchange to happen asynchronously.

Silent Payments: a fixed address without reuse

Silent Payments (BIP 352) solve the donation-address problem. You publish a single long code starting with sp1. Each sender uses their own keys to derive from it a new Taproot address valid only for that payment. On the blockchain no one can see that all the payments go to the same recipient. In return your wallet has to scan every new block, which costs more computation. As of November 2026 only a few wallets support it. How Taproot addresses work is covered in Taproot and Schnorr.

The legal position in Germany, Austria and Switzerland

Privacy is not grounds for suspicion. In none of the three countries is a private person forbidden from using fresh addresses, running their own node, paying via Lightning or taking part in a CoinJoin. What is forbidden is what's also forbidden with cash: concealing money from crimes, i.e. money laundering under § 261 of the German Criminal Code, § 165 of the Austrian Criminal Code and Art. 305bis of the Swiss Criminal Code.

Exchanges have their own duties. Providers are bound by anti-money-laundering law: the GwG in Germany, the FM-GwG in Austria, the Anti-Money Laundering Act in Switzerland. They must examine unusual payments and report suspicions. Many use chain analysis for this. A deposit coming straight from a CoinJoin can lead to questions about its origin, a freeze or a refusal. You have no right to have an exchange accept every deposit.

Stricter in the EU from July 2027. The EU Anti-Money Laundering Regulation (Regulation (EU) 2024/1624) applies from 10 July 2027. Its Article 79 forbids crypto providers from keeping anonymous accounts or offering crypto assets with built-in anonymisation. It applies to providers, not to you: it does not govern what you do in your own wallet. Switzerland is not an EU member; there, FINMA has required providers since 2019 to look closely at withdrawals to external wallets.

What you can do as a saver

For most long-term holders in the DACH region the goal isn't anonymity but discretion: strangers shouldn't see how much you have. That also reduces the risk of becoming a target for extortion or burglary, as described in Discretion and physical security. In order of increasing effort:

1. Every payment to a fresh address. No fixed donation address, no fixed savings-plan address if the exchange allows a list.
2. Keep exchange coins and other coins apart. One wallet (or account within the wallet) for purchases with ID, one for coins without. Never mix them in one payment.
3. Your own node. Your wallet only asks you, not someone else's server.
4. Use coin control. Good wallets let you choose which UTXOs a payment uses. Don't hand a merchant the note holding half your wealth.
5. Small payments via Lightning. The merchant doesn't see your on-chain balance.
6. CoinJoin only with a plan. If you mix, know that you'd better not send those coins to a regulated exchange afterwards.