In the context of blockchain irreversibility, which of the following is NOT true?

The statement regarding the predictability of hash values by a miner is not true in the context of blockchain irreversibility. In blockchain technology, the hashing process is designed to be secure and unpredictable. Miners cannot accurately predict the output of a hash function based on their input. This unpredictability is crucial for maintaining the integrity and security of the blockchain.

When miners attempt to find a solution for a block, they are essentially guessing values (often referred to as "nonce") to produce a hash that meets certain criteria (typically a hash lower than a specific target). Due to the nature of cryptographic hash functions, small changes in input can lead to drastically different output hashes. This characteristic ensures that miners cannot merely adjust data to predict future hash values.

As a result, the irreversibility of transactions on the blockchain is maintained, as altering any part of the data would require significant computational power to re-hash the affected block and all subsequent blocks. This complexity effectively secures the blockchain from tampering and provides confidence in the transactional history recorded within it.