A hash value is a cryptographic checksum generated by applying a hash function (e.g., SHA-256 or MD5) to the data. If the hash value of the captured image matches the hash value of the original media, it confirms that the image is an exact, unchanged replica. Hashing is a widely accepted forensic technique to ensure data integrity during investigations.
The file allocation table, access control list, and file size do not provide the same level of assurance regarding the exactness of the data replication as hashing does.

Blockchain provides a decentralized, immutable ledger that records transactions transparently across multiple parties. This enables nonrepudiation because once a transaction is recorded on the blockchain, it cannot be altered or denied by any party involved. Additionally, blockchain does not require a central trusted authority, as the consensus mechanism ensures trust and verification across all participants.
While PKI is also effective for nonrepudiation, it typically involves a trusted certificate authority.
Blockchain, on the other hand, eliminates the need for such an intermediary, making it ideal for scenarios where mutual trust is not required.

The most significant reason for using key performance indicators (KPIs) is that they provide timely indications of when corrective actions need to be taken. KPIs help track the progress of IT projects against their targets, enabling the project team and management to address issues early and keep the project on track.