Integrity check refers to the process of ensuring that data within a blockchain remains unaltered and secure. This is crucial because blockchain technology relies on transparency and trust. Any change to the data would undermine the entire system.In practice, integrity checks often use cryptographic hashing. Each block in a blockchain contains a unique hash that represents its data and also includes the hash of the previous block. This chaining of blocks means that if someone tries to alter the data in a block, the hash for that block—and all subsequent blocks—will change. This makes unauthorized alterations easily detectable.Regular integrity checks are fundamental for validating transactions. Miners or validators verify that all transactions are legitimate and comply with network rules before adding them to the blockchain. This process not only ensures data accuracy but also reinforces trust among users, as they can be confident that the history of transactions is secure and tamper-proof.