Is Bitcoin safe?Is Bitcoin safe and reliable?

Bitcoin's network is decentralized and secured by thousands of nodes, but your own setup matters just as much. There are two layers to bitcoin safety, and both deserve attention:

• The network itself. Decentralization, miners, and the structure of the blockchain make it extremely hard to manipulate the bitcoin network or fake a transaction.
• Your own setup. Even with a perfectly secure network, weak password hygiene, an exchange hack, or a lost backup phrase can still cost you your coins.

In the rest of this article we'll show you how the blockchain protects your coins, and how to protect them yourself.

Two design choices give the bitcoin network its security: decentralization and the chronological chain of transactions.

Decentralization. Bitcoin isn't run by a single company or government. Instead, thousands of computers, called nodes, independently verify every transaction. There are currently more than 15,000 reachable nodes around the world, plus a much larger group of miners that adds new transactions to the blockchain. To rewrite history, an attacker would need to control more than half of the total computing power on the network, a "51% attack". For a network this large, that's prohibitively expensive in practice.

A chronological chain. Every ten minutes, miners add a new block of transactions to the chain. Each block contains a fingerprint (a hash) of the block before it. Change one transaction in an old block and every block after it would also need to be rewritten, and accepted by a majority of the network. The deeper a transaction sits in the chain, the more impossible it becomes to undo. As a rule of thumb, after six blocks (about an hour) a transaction is considered final.

To override bitcoin, an attacker needs more raw computing power than the rest of the world combined. The energy bill alone would run into the millions per day, and the moment such an attack started, the bitcoin price would crash, making the attack worthless. That's why no successful attack on the bitcoin blockchain has ever happened.

Smaller cryptocurrencies have been attacked, exactly because their networks are smaller. Bitcoin's size is, in this sense, its main shield.

The network can't protect you from a stolen password or a lost backup phrase. Three habits do most of the work:

• Use a hardware wallet for long-term storage. A hardware wallet keeps your private keys offline, on a small dedicated device. Even if your laptop is compromised, your bitcoin can't be moved without the device in your hand.
• Write your backup phrase down on paper. When you set up a wallet, you get a 12 or 24-word recovery phrase. Anyone with that phrase can access your bitcoin. Anyone without it, including you, cannot. Write it on paper, store it somewhere private, and never type it into a website.
• Be careful with exchanges. Coins held on an exchange are technically the exchange's, not yours. Use exchanges to buy and sell, but move long-term holdings to a wallet you control.

When you read in the news that "bitcoin was hacked", what almost always actually happened is:

• An exchange was breached and customer balances were stolen.
• A smart contract or bridge on a different chain (often Ethereum) had a bug.
• A user was tricked into giving up their backup phrase via phishing.

The bitcoin network itself has never been broken. The lesson is that "is bitcoin safe?" is really three questions: is the network safe (yes), is your wallet setup safe (depends on you), and is your provider safe (do your research).

At BTC Direct we're registered as a crypto service provider in the Netherlands and operate under the European MiCA framework, which sets requirements for capital reserves, customer due diligence, and how customer funds are segregated.