The hash function (SHA256) also plays an important role in Bitcoin's Proof-of-Work consensus algorithm, particularly in the block validation process.
Recently, a tweet by a well-known crypto investor (@cobie) about an alleged "red notice" issued by Interpool against CZ caused a wave of concern in cryptospace, even having a negative impact on $BTC and $BNB prices.
The peculiarity of the tweet in question is that it is a sequence of numbers and letters, meaningless at first glance.
It's actually a hash, i.e. the result of a hash function, a mathematical function that converts any input signal to a string of bytes of a given length.
SHA256: Bitcoin's hash function
SHA256 (Secure Hash Algorithm), the hash function involved in Bitcoin block validation, was chosen because of its efficiency: it is able to generate output using very little processing power, while making it extremely difficult to trace the input data.
All output data generated by SHA256 is a string of 64 letters and numbers, regardless of the type of input data. In fact, even with input data of different lengths, such as "Satoshi Nakamoto" or "Bitcoin", the output will still be 64 characters. Indeed:
Satoshi Nakamoto:
a0dc65ffca799873cbea0ac274015b9526505daaaed385155425f7337704883e
Bitcoin:
b4056df6691f8dc72e56302ddad345d65fead3ead9299609a826e2344eb63aa4
In Bitcoin, SHA256 is used both in the creation of new network addresses and in the mining process, in which miners use a hash function to find an output that meets the complexity criteria required by the network to solve the cryptographic puzzle and receive a $BTC reward and a portion of the commissions generated by the network.
Thus, SHA256 is the backbone of Bitcoin's proof-of-work system because without it, the network would not be immutable, let alone able to prove who owns $BTC, in what amount, and at what time.
One concern about the security of the hash function has to do with quantum computers, which due to their lightning-fast computing power can solve Bitcoin cryptographic puzzles effortlessly, which would compromise the security of the network.
Although this technology has not yet reached a high level of popularity, in the future, thanks to technological advances, the cost may come down, leading to an increase in the proliferation of these high-performance computers.
Will quantum computers become the end of Bitcoin or can the Hodlers sleep easy?