Which measure is essential for ensuring data is securely disposed of after its retention period?

The essential measure for ensuring data is securely disposed of after its retention period is destruction. This involves completely eliminating data in such a way that it cannot be recovered or reconstructed by any means. Secure data destruction can include methods such as physical destruction of storage devices, overwriting data with random patterns, or utilizing specialized software designed to irreversibly erase data.

When data is no longer needed and reaches the end of its retention period, it is crucial to dispose of it properly to prevent unauthorized access or potential breaches. Effective destruction ensures compliance with regulations regarding data protection and privacy, mitigating risks associated with holding onto sensitive information longer than necessary.

In contrast, encryption secures data while stored but does not address the issues of disposal; archiving preserves data for future reference, which is opposite to the need for disposal; and redaction involves editing or obscuring parts of data rather than eliminating it entirely. Therefore, destruction is the correct and necessary measure for secure data disposal.