To “hack” bitcoin, you need control over half of the network’s hashrate and mine transaction blocks faster than the rest of the honest miners. Such an attack would allow you to censor new transactions, double spend coins, or rewrite the blockchain itself. However, it’s practically impossible to achieve this since you would need an incredible amount of computational power and money to bypass the network’s safeguards. Here’s why…

The hashrate refers to the total amount of computational effort being used to process and secure all incoming transactions on the network. As of this post’s publishing, the hashrate is roughly 885 exahashes/second. For reference, one exahash is 10^18 or 1,000,000,000,000,000,000 hashes. Hashes are unique, fixed-length alphanumeric strings that are utilized in cryptography and Bitcoin. When a transaction is created, the details of the sender, receiver, and BTC amount are converted into a hash. You might’ve come across the term “hash function”, too, which refers to the abstract concept of how a mathematical function transforms an input of any size into a fixed-size output. In our case, the specific algorithm the Bitcoin network utilizes for generating hash functions is the SHA-256 hash algorithm as depicted below.

String Input SHA-256 HASH Output
Why You Can’t Hack Bitcoin 6eef7e8b1e947b933431f3ca66819197817d63be777e22224b780f76930d2c28
Why You Cant Hack Bitcoin a5b1a085edfd0dcd67e34b5ef9f6d0cf73044d36123960fdb2ec3733ed9f61b0d
GenZGuideToBitcoin e5fd8834530c07106acee9a5aa91464b766638f2188cb3c064ddd067735b591

Basically, Bitcoin’s blockchain is secured using a proof-of-work system where the longest chain of confirmed transactions represents the valid blockchain; so altering even a tiny detail in one block would invalidate all subsequent blocks, as each block’s hash depends on the preceding block’s hash. What is essentially happening with mining is thousands on computers are solving cryptographic puzzles, and like a lottery, the computer-or group/pool of computers- that solves the puzzle first adds the next block of transactions to the Bitcoin public record and earns some Bitcoin for their hard work.

Bitcoin’s network also implements a difficulty adjustment every 2,016 blocks (roughly every two weeks) to ensure blocks are mined approximately every 10 minutes. If blocks are mined too quickly or slowly, the difficulty adjusts accordingly. An attacker would not only need to overcome the current computational difficulty but also keep pace with the increasing difficulty triggered by their attack.

We’ll quantify the cost of an attack here. Your goal is to achieve a hashrate of 442.5 exahashes/second (51% of the network) and outpace every other honest miner. To achieve this, your miner of choice is the Bitmain Antminer S19 XP Hydro which boasts an impressive hashrate of 225 terahashes/sec (1 TH = 10^9 hashes). With one exahash being the equivalent of 1,000,000 terahashes, you would need 1,966,667 miners costing a total of around $12.8 billion. Operating just these miners would demand 10.4 gigawatts of power and your electric bill would total ~$376 million a month or ~$4.5 billion a year.

And that’s just the start. The difficulty adjustment would quickly render your hashrate insufficient, requiring you to purchase and deploy additional miners. Other costs include maintenance, labor, logistics, and planning. Even with unlimited funds, a compromise in the network’s security would probably result in a substantial price crash, therefore further neutralizing the financial incentive.

In conclusion, the combination of cryptographic integrity, difficulty adjustments, and immense costs makes hacking Bitcoin nearly impossible. So, don’t hack Bitcoin…it’s a losing game.