dash-docs/en/bitcoin-core/features/privacy.md

id	layout	lang	columns	title	breadcrumbs	third_party_privacy
bitcoin-core-privacy	base-core	en	1	Privacy - Bitcoin Core Features	bitcoin bcc bcc features Privacy	name css_class group tracks_real_names knows_your_bitcoin_balance susceptible_to_taint_analysis tracks_payments tracks_amounts tracks_ip_addresses Bitcoin Core bitcoin_core default-show no no yes no no no name css_class group tracks_real_names knows_your_bitcoin_balance susceptible_to_taint_analysis tracks_payments tracks_amounts tracks_ip_addresses BitGo bitcoin_go not-displayed no yes yes yes yes yes name css_class group tracks_real_names knows_your_bitcoin_balance susceptible_to_taint_analysis tracks_payments tracks_amounts tracks_ip_addresses Blockchain.info blockchain_info not-displayed no yes yes yes yes yes name css_class group tracks_real_names knows_your_bitcoin_balance susceptible_to_taint_analysis tracks_payments tracks_amounts tracks_ip_addresses Coinbase coinbase default-show yes yes no yes yes yes name css_class group tracks_real_names knows_your_bitcoin_balance susceptible_to_taint_analysis tracks_payments tracks_amounts tracks_ip_addresses GreenAddress greenaddress not-displayed no yes yes yes yes yes

Bitcoin Core's Excellent Privacy

{:.not-displayed}

{% include bitcoin-core/download-bitcoin-core.html %}

What if every time you spent or received cash, all the transaction details were published to your Twitter or Facebook feed for all your friends to see? You probably wouldn't want to use cash any more.

Every confirmed Bitcoin transaction is published to the block chain where anyone can see it. So why do people still use Bitcoin? And why do many of them believe that Bitcoin is a private way of sending money?

One reason is that Bitcoin Core and some other Bitcoin software tries to avoid associating your real-world identity with the transactions you make. The difference looks like this:

The second type of transaction (a pseudonymous transaction) only provides practical privacy if nobody can figure out that "5a35b" is really Alice. It's up to your wallet to prevent anyone from making that connection. See below for how Bitcoin Core's privacy compares to other wallets.

No Sign-Up Required

Third-party Bitcoin services can both increase and decrease your privacy. They can increase it by mixing your transactions with those of other users; they can decrease it by tracking your activity and directly associating it with your real name or other identifying information.

Click an entry below to show it:

{% for service in page.third_party_privacy %} {% if service.name != 'Bitcoin Core' %} <button {% if service.group == "default-show" %} class="js showcolumn active" {% else %} class="js showcolumn" {% endif %} id="{{service.css_class}}" >{{service.name}} {% endif %} {% endfor %}

{% comment %} {% endcomment %} {% for service in page.third_party_privacy %} {% if service.name %} {% else %} {% die "Some service doesn't have a name" %} {% endif %} {% endfor %} {% for service in page.third_party_privacy %} {% case service.tracks_real_names %} {% when "yes" %} {% when "no" %} {% when "maybe" %} {% else %} {% die "missing service information" %} {% endcase %} {% endfor %} {% for service in page.third_party_privacy %} {% case service.knows_your_bitcoin_balance %} {% when "yes" %} {% when "no" %} {% when "maybe" %} {% else %} {% die "missing service information" %} {% endcase %} {% endfor %} {% for service in page.third_party_privacy %} {% case service.tracks_payments %} {% when "yes" %} {% when "no" %} {% when "maybe" %} {% else %} {% die "missing service information" %} {% endcase %} {% endfor %} {% for service in page.third_party_privacy %} {% case service.tracks_amounts %} {% when "yes" %} {% when "no" %} {% when "maybe" %} {% else %} {% die "missing service information" %} {% endcase %} {% endfor %} {% for service in page.third_party_privacy %} {% case service.tracks_ip_addresses %} {% when "yes" %} {% when "no" %} {% when "maybe" %} {% else %} {% die "missing service information" %} {% endcase %} {% endfor %} {% for service in page.third_party_privacy %} {% if service.name %} {% else %} {% die "Some service doesn't have a name" %} {% endif %} {% endfor %} {% for service in page.third_party_privacy %} {% case service.susceptible_to_taint_analysis %} {% when "yes" %} {% when "no" %} {% when "maybe" %} {% else %} {% die "missing service information" %} {% endcase %} {% endfor %}

Who knows your information? **Just you**{:.fggreen} or also a **service provider?**{:.fgred}
	{{service.name}}
Your real name
Your bitcoin balance
Who you pay, and/or who pays you (in some cases)
How much you spend and/or receive
The IP address your connection came from
Who can guess your information? **Just you**{:.fggreen} or also **people you trade with?**{:.fgred}
	{{service.name}}
Other transactions you made or received

Perfect Privacy for Received Transactions

There are {{site.text.total_tx_count_in_millions}} million transactions on the Bitcoin block chain. How do you find which ones pay you? Here are some common options:

<td class="center" markdown="span">**Ask random nodes**{:.fgred}<br
  >Some of which sell your data<br><br
  ><button class="popup js" data-container="bloom_filter_receiving">P2P lightweight wallets</button></td>

<td class="center" markdown="span">**Get all {{site.text.total_tx_count_in_millions}} million transactions**{:.fggreen}<br
  >For **perfect** receiving privacy<br><br
  >**Bitcoin Core**</td>

**Ask bankers**{:.fgred} They'll monitor your every transaction Bitcoin banks

**Ask a free service**{:.fgred} (Actually, some do care about privacy) Client lightweight wallets

Bitcoin Core downloads all {{site.text.total_tx_count_in_millions}} million transactions on the Bitcoin block chain and processes them to find which transactions pay you.

This currently takes about {{site.text.typical_ibd_time_in_hours}} hours the first time you start Bitcoin Core and about {{site.text.typical_144_block_catchup_time_in_minutes}} minutes a day to keep updated, but it gives you what scientists call information-theoretic (perfect) privacy against eavesdroppers for received transactions.

Strong Privacy for Sent Transactions

To put a transaction on the block chain, you must send it publicly---but how you send it can make a big difference.

Can you guess who made which transactions? Nearly all peer-to-peer lightweight clients today make no attempt to obscure their sent transactions. They simply send them to some or all of their peers.

Bitcoin Core does much better. By default, it relays transactions for all of its peers---thousands of separate transactions a day under common conditions---which allows it both [support the peer-to-peer network][bcc network support] and confuse anti-privacy organizations that try to track your transactions.

Tor Compatible

The Tor anonymity network helps disassociate your online activity from your IP address (which is often closely associated with your real name). This significantly increases your ability to confound anti-privacy organizations.

Once you [setup Tor][], using it with Bitcoin Core is [easy][bcc tor]. If you also [setup a Tor hidden service][bcc tor hs], you will be able to [connect mobile clients][bcc user interface lightweight] to your Bitcoin Core full node for increased security and privacy wherever you go.

{:.right-hanger} [Start using Tor today ][setup tor]

Decentralized Peer Discovery

The first time any Bitcoin program connects to the peer-to-peer network, it has to ask a centralized authority for a list of recommended peers.

Once the program gets on the network, it can ask its peers for more recommendations in a fully decentralized way---but most lightweight wallets don't bother.

<td>Uses the peer-to-peer network to independently discover new
peers.  Uses found peers on restart.</td>

P2P Lightweight Wallets	Bitcoin Core
Asks the same centralized services every time program is restarted. This can be faster.

This allows the centralized authority to connect lightweight wallets to dishonest peers that can completely destroy lightweight transaction privacy. Those dishonest peers can work with dishonest miners to weaken lightweight security too.

Bitcoin Core prefers decentralized peer discovery, so after the first time it starts, it no longer has to trust the centralized authority. Isn't that worth occasionally starting up a few seconds slower?

**Previous Feature**
[Validation][bcc validation] **Next feature**
[Requirements][bcc requirements]


When you receive bitcoins to a Bitcoin bank, the money is sent to one of the bank's addresses---not your own---which can give you excellent privacy against random strangers.

However, the bank knows you received the transaction and they can likely also see any information you associate with the transaction, such as the sender's name or another note you attach to the transaction.

The bank may also be required by law to disclose information about your account. They can also sell your information or have a hacker steal your information.


By only asking for payments related to your wallet, plus maybe a few others as bloom filter camouflage, lightweight wallets may reveal who you paid, who paid you, and what your current bitcoin balance is.

A [2014 study of lightweight clients][study of SPV privacy over tor] said, "Our results show that bloom filters incur serious privacy leakage in existing SPV client implementations [...] such an information leakage might severely harm the privacy of users" Nearly all lightweight clients are still vulnerable today.

Learn more: ["Lying consistently is hard"][lying consistently is hard]


Some lightweight wallets don't connect to the Bitcoin peer-to-peer (P2P) network. Instead, they make a (usually secure) connection to a single server that provides block chain data.

The wallet tells the server all of its addresses, and the server replies with all of the transactions that belong to the wallet. This explicitly reveals all of your addresses, which is bad for your privacy---but it only gives that information to one server, as long as you don't change servers later.

The server can, of course, give away your information and further reduce your privacy. However, as of {{site.text.assertion_month | date: "%B %Y"}}, most of these types of servers are run by volunteers who likely want to help protect your privacy, so this model can be more private than bank wallets or P2P lightweight wallets.

The following P2P lightweight wallets use decentralized peer discovery by default.

• BreadWallet

If you know of another compliant lightweight wallet, please [tell us about it][docs issue].

Information-theoretic privacy means that the privacy can't be broken even if an attacker has unlimited computing resources.

Learn more: [Information theoretic security][] (Wikipedia)

{% include references.md %}