SSCP Cryptography Practice Question
Which of the following is a method to check the revocation status of a digital certificate in real-time without the client downloading a full list?
⚠ Common exam trap
SSCP often tests the difference between CRL (batch, download-heavy) and OCSP (real-time, per-certificate) — candidates pick CRL because it's the more familiar revocation concept, missing the 'real-time without downloading a full list' qualifier.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Online Certificate Status Protocol (OCSP)
OCSP (Online Certificate Status Protocol) lets a client query a responder in real time for the revocation status of a specific certificate, returning 'good,' 'revoked,' or 'unknown' without downloading the entire CRL. It is defined in RFC 6960 and is the standard real-time alternative to CRLs. This matches the requirement exactly.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Certificate Revocation List (CRL)
Why it's wrong here
A CRL requires the client to download the entire signed list of revoked serial numbers, contradicting the requirement to avoid full-list retrieval. It is tempting because CRLs are a standard revocation mechanism, but their batch, periodically published format is exactly what OCSP was designed to replace.
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Self-signed certificate validation
Why it's wrong here
Self-signed certificate validation concerns trusting a certificate whose issuer and subject match; it says nothing about revocation status. It is tempting because self-signed certificates bypass CA chains, but no revocation checking mechanism exists within that model, so it cannot satisfy a real-time status query.
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Online Certificate Status Protocol (OCSP)
Why this is correct
OCSP queries a responder directly about a single certificate's status, returning good, revoked or unknown in real time. Unlike a CRL, the client never downloads the full revocation list, which satisfies the requirement for immediate status checking without bulk list retrieval.
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Certificate Transparency (CT)
Why it's wrong here
Certificate Transparency provides append-only public logs of issued certificates to detect mis-issuance; it does not report whether a certificate has been revoked. It is tempting because CT offers real-time log monitoring without downloading lists, but its purpose is auditing issuance, not querying revocation status.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
This SSCP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SSCP exam.