Is it safe to share your Bitcoin address?

 In Tutorial

Answer: Your wallet address is designed to be shared with people! A bitcoin wallet address is a receive only address, so you cannot use it to send bitcoin. Thus, it is mostly safe to share it with anyone.

However, it is easy to confuse a Bitcoin address and a private key — and you should never give away your private key. Read the full article to learn more about Public key and Bitcoin Address.

What is a Bitcoin Address and how it works

A Bitcoin address is essentially an email address for people to send you Bitcoin. A Bitcoin address is generated from the Public key by hashing it twice. Many wallet providers change your wallet address after every transaction. This is done to protect the anonymity of the users and prevent cyber-stalking of their accounts.

A Bitcoin address example

A Bitcoin address 19Lm8aB8tfbjAVHGYymMqRrCYiqmAtJSPy portrayed as a QR-code.
Never send your coins to this address. It’s for educational purposes only!

What is a Bitcoin Public key

When you create a Bitcoin Wallet, a pair of keys is generated using complex codes and mathematical algorithms. In result, you have two keys: your Public key and Private key. The Public key is mathematically derived from the Private key.

The Private and Public keys are large integer numbers and are usually represented using a separate Wallet Import Format (WIF) consisting of letters and numbers. A simple Public key in WIF looks like this:

19Lm8aB8tfbjAVHGYymMqRrCYiqmAtJSPy

Your Public key cannot be changed as it is linked to your Private key. However, many bitcoin wallets, e.g. Bonpay, provide you with some Bitcoin Address, which is a result of the hash of your Public key and some additional information. This can be changed after every transaction or upon your will anytime.

private-public-keys-address

With a Public key or Address, you can:

  • view the state of your Bitcoin wallet;
  • share it to receive funds;
  • check the history of all operations made on the wallet.

Nobody can access the wallet and steal your money if they know only your Public key or Address.

What is a Bitcoin Private key

Bitcoin Private key is similar to a public key, but it has different levels of access to your wallet.

A public key (left) and a private key (right), created on BitAddress.org
Never send your coins to this address. It’s for educational purposes only!

 

With a Private key, you can transfer bitcoin from the wallet to another address. If you give someone your Private key — you are giving away the wallet with all your funds.

How is a private key different from a password

While a private key is very similar to a password, it has a difference.

Usually, a password is used to access some account, e.g. your online banking account. When you want to transfer some money to buy a book, you have to confirm your transaction with a PIN number or a secret code sent to your mobile phone number.

Private key is used to access your wallet too. However, you sign the cryptocurrencies you send to others using a Private Key. This means that all inbound and outbound transactions have some hashed part of your Private key.

If a hacker has your bank account password, you can recover access by contacting your bank support. If someone has your private key, the only thing you can do to transfer funds somewhere else before them. Otherwise, your funds are lost, and no one can help you.

Can you get a Private key from a Public key?

If a Public key is made from a Private key, couldn’t someone create a reverse key generator and get a Private key from any Public key?

Actually, no.

Cryptocurrencies use a complicated mathematical algorithm to generate Public keys. This algorithm is designed in the way that it is easy to generate Public keys from private keys, but it is almost impossible to reverse the process.

In a Reddit thread they discussed this possibility and found out that if someone wanted to reverse math your public key to find your private key, it would take the world’s most powerful computer something like 43928409382490832904839028490328 years to perform the calculation, because of math.

How to look up a Bitcoin address

If you have somebody’s Bitcoin address and want to look up how much Bitcoin they have, you need to:

  • Go to Blockchain.info;
  • Enter the address to the search field;
  • Click the Search button.

That’s it! Now you can see the account balance and the list of transactions for this wallet. And so does anyone else — anyone can look up any Bitcoin address, as long as they know it.

Why you should generate a new address after each transaction

Generating a new address after each transaction seems like a foreign concept to many people. After all, you do not need a new bank account after each payday, nor do you have to reissue the banking card.

When you give your address to anyone, they can check how much money you have and see all your previous transactions. You can’t prevent this — however, you can prevent them from seeing your future transactions by generating a new address that they do not know about.

How to keep your Bitcoin address safe

If you do not want for people to spy on you via your Bitcoin address, here are some tips on staying safe.

  1. Generate a new address after using the previous one. While it may still work, the old key can be used to track the state of your wallet. Most software will do it for you, but if it doesn’t — make sure that you generate a new address manually.
  2. Use online wallets as proxies. Online wallets are using a single wallet with millions of addresses to process payments, which makes them perfect to stop cyber-stalking. Simply accept the payments to your wallet on an exchange and then transfer them to your main one, and no one will be able to spy on you.
  3. Do not mix up your private key and your public key. Just don’t. Both look relatively similar, so it’s easy to get confused. You’d instead don’t store keys close to each other so you won’t mix them.

Now you know that it is relatively safe to give out your Bitcoin address. However, you still have to take some measures to ensure your privacy after you’ve done so.

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