Data integrity is the assurance that digital information is uncorrupted and can only be accessed or modified by those authorized to do so. Integrity involves maintaining the consistency, accuracy and trustworthiness of data over its entire lifecycle.
To maintain integrity, data must not be changed in transit and steps must be taken to ensure that data cannot be altered by an unauthorized person or program. Such measures include implementing user access controls and version control to prevent erroneous changes or accidental deletion by authorized users. Other measures include the use of checksums and cryptographic checksums to verify integrity. Network administration measures to ensure data integrity include documenting system administration procedures, parameters and maintenance activities, and creating disaster recovery plans for occurrences such as power outages, server failure or security attacks. Should data become corrupted, backups or redundancies must be available to restore the affected data to its correct state.
Measures must also be taken to ensure integrity by controlling the physical environment of networked terminals and servers because data consistency, accuracy and trustworthiness can also be threatened by environmental hazards such as heat, dust or electrical problems. Some means must be in place to detect any changes in data that might occur as a result of non-human-caused events such as an electromagnetic pulse (EMP) or server crash. Practices followed to protect data integrity in the physical environment include keeping transmission media (such as cables and connectors) covered and protected to ensure that they cannot be tapped, and protecting hardware and storage media from power surges, electrostatic discharges and magnetism.