Understanding Cryptographic Hash Functions
A cryptographic hash function is an algorithm that transforms an arbitrary data string of varying length into a fixed-length and formatted output, known as the hash.
It operates through a repeatable sequence of specific actions.
However, this simplistic approach is not suitable for cryptographic purposes. Practical hash functions possess several important characteristics:
- Easy computation: Calculating the output for any given input should be straightforward.
- Irreversibility: It should be computationally infeasible to reverse the process and determine the original input from a known output.
- Determinism: Providing the same input to the algorithm must always produce the same output.
- Collision resistance: It should be highly improbable for two different inputs to generate the same output.
- Avalanche effect: Modifying even a single bit of the input data should result in a significantly different output.
Hash functions find applications in various scenarios, such as serving as checksums to verify file integrity during transmission or storage and in randomizing functions.
Ensuring Integrity in Bitcoin Creation
The pseudorandom nature of hashes and the impossibility of predicting an output for a given input without running it through the hash function ensure that miners cannot create new Bitcoins out of thin air. They must demonstrate the computational work they have performed to earn their rewards.