What is a cryptographic hash and its significance?

A cryptographic hash is an algorithm that transforms input data of arbitrary length into a fixed-size string. This process is irreversible, meaning that the original data cannot be restored from the hash. Hashes are widely used in blockchain technology to ensure transaction security. They guarantee data integrity and are also used for creating digital signatures and verifying the authenticity of messages. Thanks to hashing, falsifications and data manipulations can be avoided, making blockchain technology reliable and secure.