What makes Bitcoin Blockchain Secure?

The Bitcoin blockchain has proven highly resilient over its more than ten-year history. That's what protects him from attack.

Compromising and gaining control of the Bitcoin network is a challenging prospect.

Bitcoin is cryptographic, irreversible, distributed, and publicly available.

The selection of private keys or the capture of the blockchain by controlling 50% of the network's computing power is almost impossible.

Choose the name of some company, and most likely, it has already been hacked! Since 71% of hacks are financially motivated, the question arises: is it possible to hack the Bitcoin network? After all, it's a tempting target with a market capitalization of almost $335 billion.

Over its more than ten-year history, Bitcoin has proven to be surprisingly resilient to shocks and stresses. And while cryptographic exchanges have been hacked with great frequency, and their Bitcoin reserves are being redistributed, actually being under threat, whereas taking control of the Bitcoin network itself is a much more difficult prospect.

Bitcoin is cryptographic, irreversible, distributed, and publicly available.

Bitcoin uses public-key cryptography.

Bitcoin is the original cryptocurrency. "Crypto" is short for cryptography; more specifically, "public-key cryptography." This means that it uses private and public keys to ensure the authenticity and integrity of transactions. Bitcoin digital signatures are signed using the so-called elliptic Curve Digital Signature Algorithm (ECDSA).

The only way to get a private key from a given public key is a brute force search, trying all possible values of the private key and checking whether it has generated the corresponding public key. In practice, this is not possible since there are 1077 possible combinations.

Bitcoin transactions are irreversible.

The smartest thing about Bitcoin is that it runs on the blockchain. A "block" is simply a batch of recently processed transactions. A one-way cryptographic function links each block to the previous set of transactions, forming a "chain".

Blockchains are write-only registries. You can add information to them, but blocks cannot be changed once recorded. It's as if all transactions are buried under the weight of other blocks.

This means that people cannot simply cancel a transaction made a week ago, as your credit card company can do after you "accidentally" bought some dog wig on Amazon.

Bitcoin uses a distributed registry.

The traditional financial ecosystem relies on centralized parties, such as banks, to keep transactions and prevent fraudulent transactions. But this means that you rely on these parties to act in good faith; either can adjust the transaction registry to forge or cancel the transaction.

Blockchains are different; they are a kind of distributed registry technology. Instead of storing your money in a centralized database vulnerable to a single point of failure, it's kind of everywhere (or, more precisely, transaction records are distributed among many different parties).

It may seem not reasonable, but it's not. Everyone who runs Bitcoin software with a "node" - a computer - is responsible for verifying transactions. Most nodes have to more or less agree that the transaction record is accurate before it can be approved. (Don't worry: this is automated, so no one clicks "Agree" every 10 minutes when a new block is created).

To hack the blockchain, they will need more than to hack a regular system. For the Bitcoin blockchain to carry out such an attack, it will require acquiring and coordinating resources outside even the most powerful countries.

With so many different people using the software and a collective interest in preserving the security of a valuable coin, this is unlikely to happen. It's too expensive and too difficult to coordinate.

The Bitcoin blockchain is publicly available.

Everyone can see transactions in the Bitcoin blockchain. This is a public book. Although this means that someone can see what is in your wallet, they don't know that it belongs to you because your funds are in a pseudonymous address. Moreover, they can't take your money. Only the person who owns the private key to the bitcoin address can transfer funds.

What is especially important, because of this transparency, everyone can see the transaction log, and anyone can check the system, which causes trust.