A cryptographic key management policy is being drafted for a financial services platform that handles cardholder data, and the lead engineer is mapping the policy controls to the formal phases of the cryptographic key lifecycle. The team is debating where, in the lifecycle, the act of formally retiring a key from active use while still retaining it for verifying past signatures or decrypting archived data belongs. Which lifecycle phase BEST captures this state?
- AKey destruction, because the operational use of the key has ended and the cryptoperiod has expired.
- BKey suspension, because the key is temporarily withdrawn pending an investigation but may be reinstated for operational protection of new data.
- CKey revocation, because the trust placed in the key has been withdrawn and relying parties must be informed via the revocation infrastructure.
- DKey archival, because the key has left active operational use but is retained under controlled conditions for verifying existing signatures or decrypting previously protected data. Correct
Why A is wrong: Destruction zeroises the key material and removes any possibility of further use; the scenario explicitly retains the key for verifying old signatures and decrypting archives, which is incompatible with destruction.
Why B is wrong: Suspension is a reversible, investigative pause that contemplates returning the key to active protective use, whereas the scenario describes a permanent end to new protective use while preserving legacy verification and decryption only.
Why C is wrong: Revocation signals to relying parties that the key is no longer trustworthy, typically because of compromise or change of subject status, and forbids further reliance on signatures or ciphertext bound to it; the scenario describes routine end-of-cryptoperiod retirement with continued legitimate verification, not loss of trust.
Why D is correct: Archival is the lifecycle phase in which a key is withdrawn from active protection of new data yet kept under tightly controlled storage for legitimate residual purposes such as verifying historical signatures and recovering archived ciphertext, which matches the scenario exactly.