The Bitcoin blockchain has proven to be remarkably resilient over its decade-plus history.
In short, compromising and controlling the Bitcoin network is a challenging prospect. Because Bitcoin is cryptographic, immutable, distributed, and public. Brute-forcing private keys, or hijacking the blockchain by controlling 50% of the network’s computing power, is all but impossible.
Name a company, and, it’s been hacked. After all, it’s a tempting goal. We never say never to decrypt, but the answer is: pretty much no. And while crypto exchanges have been hacked with disappointing frequency, and their stores of Bitcoin redistributed, actually compromising and taking control of the Bitcoin network is a far more terrifying prospect. Because Bitcoin is cryptographic, immutable, distributed, and public. Public Key Cryptography Bitcoin is the original cryptocurrency. “Crypto” is short for cryptography, more specifically, “public key cryptography.” This means it uses a private and a public key to ensure the authenticity and integrity of transactions. Bitcoin digital signatures are signed using something called the Elliptic Curve Digital Signature Algorithm (ECDSA). The only way to derive the private key from a given public key is to do a brute-force search—trying every possible value for a private key and seeing if it produces the corresponding public key. In practical terms, this is impossible, since there are 1,077 possible combinations. Transactions are immutable The clever thing about Bitcoin is that it runs on a blockchain. A “block” is a batch of newly processed transactions. Each block is linked to the previous batch of transactions by a one-way cryptographic function, forming a “chain”. Blockchains are write-only ledgers. You can add information to them, but blocks, once written, cannot be changed. It’s as if all transactions are buried under the weight of other blocks. This means that people can’t simply reverse a transaction from a week ago like your credit card company can after you “accidentally” made that ill-advised purchase on eBay.