For long-term storage of backup data in the cloud, encryption is a fundamental security control. Access to this encrypted data is entirely dependent on the availability of the corresponding decryption keys. A robust key management plan, which governs the entire lifecycle of cryptographic keys (generation, storage, use, archival, and destruction), is essential. If the keys are lost, corrupted, or the systems managing them become obsolete, the organization will permanently lose access to its own encrypted backup data. Therefore, addressing key management is the most critical factor to prevent this specific risk.

A. Quantum computing: This is a future threat to the confidentiality of current encryption algorithms, not a direct cause of losing access due to current operational mismanagement.

B. Change tracking: This is a process for monitoring modifications to data or configurations, which is important for integrity and auditing but does not control access to the data itself.

D. Regulatory compliance: This involves adhering to laws and standards. While compliance may mandate encryption and key management, it is the failure of the technical control (key management) itself that causes the loss of access.

1. National Institute of Standards and Technology (NIST) Special Publication 800-57 Part 1

Rev. 5

Recommendation for Key Management. Section 8.1.6

"Key Archival

" states

"If an archive of cryptographic keys is not maintained

access to the encrypted data will be lost when the keys are destroyed. Therefore

the loss of an archive of keys used to encrypt stored data may be catastrophic."

2. Cloud Security Alliance (CSA)

Security Guidance for Critical Areas of Focus in Cloud Computing v4.0. In Domain 11: Data Security and Encryption

the document emphasizes

"Proper key management is the most important aspect to get right when using cryptography... If keys are not properly secured

the entire security of the encryption is negated. If keys are lost

so is the data." (p. 121).

3. Armknecht

F.

& Westhoff

D. (2012). Security and Trust in Cloud Systems. In Secure Cloud Computing (pp. 3-19). Springer. This academic text discusses the challenges of cloud security

noting that for long-term data storage

"the long-term secure management of the corresponding keys is a major challenge. The loss of a key usually implies the loss of all data encrypted with it." (Section 2.2

Challenges).