CISSP - Security Architecture and Engineering (13% of the exam) - Section 3.6

Select and determine cryptographic solutions including cryptographic lifecycle, methods, and public key infrastructure (PKI).

Compare symmetric and asymmetric cryptographic methods, describe PKI components including certificate authorities and key management lifecycles, and recognise the implications of quantum cryptography for current algorithms. Select the appropriate cryptographic solution for a given confidentiality, integrity, or non-repudiation requirement.

symmetric cryptographyasymmetric cryptographyPKIkey managementquantum cryptography

Practice question for this objective

Free sampleSecurity Architecture and Engineeringhard

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BKey suspension, because the key is temporarily withdrawn pending an investigation but may be reinstated for operational protection of new data.
CKey revocation, because the trust placed in the key has been withdrawn and relying parties must be informed via the revocation infrastructure.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

Place a key that has ended active protection but remains needed for legacy verification or decryption into the archival phase of the cryptographic lifecycle. NIST SP 800-57 separates the cryptographic key lifecycle into operational phases that include activation, active use, deactivation, archival, and destruction, along with compromise responses such as revocation and suspension. Archival is specifically defined as the controlled retention of a deactivated key so that relying parties can still verify historical artefacts or recover data that was protected under that key, without exposing the key to new protective use.

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.

See more CISSP practice questions, answers explained.

Exam traps in Security Architecture and Engineering

Answers that look right on this material and are not. Each one is a distractor from a different question in the CISSP bank for this domain.

Ransomware brute-forces the victim's existing file encryption keys so the attacker can replace them with their own.
Why it is wrong: Brute force is computationally infeasible against modern symmetric keys, and ransomware does not need to break existing keys. It simply encrypts the plaintext files with its own freshly generated key.
AES in Electronic Code Book mode with PKCS#7 padding and a stored SHA-256 hash of each plaintext for tamper detection.
Why it is wrong: ECB leaks equality between repeated plaintext blocks, which is exactly the weakness the scenario flags, and a stored hash of the plaintext does not bind the integrity check to the ciphertext or the key, so an attacker who swaps ciphertexts is not detected by this construction.
It signs and publishes a periodically refreshed list of all revoked serial numbers that relying parties download in full before validating any presented certificate.
Why it is wrong: That description matches a certificate revocation list distribution point rather than an OCSP responder; CRLs are bulk static artefacts pulled at intervals, while OCSP is designed precisely to avoid forcing relying parties to download and parse the entire revocation list.

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