5.2 Quiz: Symmetric Cryptography

AP Cybersecurity · Unit 5 · Topic 5.2 · Quiz

5.2 Checkpoint: Symmetric Cryptography

Five exam-style questions. Each tests a distinction the AP exam loves: algorithm vs mode, symmetric vs asymmetric, confidentiality vs integrity, strong algorithm + weak key management.

5 Questions~10 minScored · Exam-style

How to Approach

Predict-first: read the scenario, commit to a category (algorithm / mode / IV / key management), then look at options.

Remember: ECB never for bulk. AES + right mode + separate keys is the recipe. 3DES/DES/RC4/MD5/SHA-1 in modern contexts = deprecated.

Score0 / 5
Question 1
An organization still uses 3DES-CBC for encrypting payment data at rest. Their security consultant flags this. Why is 3DES flagged despite running DES three times?
✎ Predict before reading options. Commit to your answer first.
Exam Tip3DES, DES, RC4, MD5, SHA-1 in modern scenarios = formal deprecation = vulnerability.
Question 2
Consider the following four statements about modes of operation. Which is TRUE?
✎ Predict before reading options. Commit to your answer first.
Exam TipGCM = AEAD = confidentiality + integrity. Canonical modern default.
Question 3
A developer proposes encrypting all user Social Security numbers in the database with AES-256-ECB. A colleague says, 'AES-256 is unbreakable — that's secure enough.' What is the correct response?
✎ Predict before reading options. Commit to your answer first.
Exam TipECB for fields = value equality leaks between records. Use GCM or CBC with random IVs.
Question 4
Which statement most accurately describes the relationship between symmetric and asymmetric cryptography in modern TLS?
✎ Predict before reading options. Commit to your answer first.
Exam TipAsymmetric for key exchange. Symmetric for bulk data. This is why both exist and why 5.2 and 5.4 connect.
Question 5
A service encrypts large data files with AES-256-GCM. The team notices that they occasionally get decryption failures where GCM reports that the authentication tag doesn't match. A developer suggests, 'let's ignore the tag mismatch and return the decrypted data anyway for better user experience.' What is the correct response and why?
✎ Predict before reading options. Commit to your answer first.
Exam TipAEAD tag mismatch = fail closed. Never return 'decrypted' data from a failed tag verification. That's what the tag is for.

Quiz Complete

— / 5

—

← Back to Lab Next Lesson: 5.3 →
AP Cybersecurity · Unit 5 · Lesson 5.2 · Quiz
Lesson•Exercise 1•Exercise 2•Lab•Quiz•
Back to:Lesson 5.2Unit 5 Study GuideCourse Guide

Get in Touch

Whether you're a student, parent, or teacher — I'd love to hear from you.

Just want free AP CS resources?

Enter your email below and check the subscribe box — no message needed. Students get daily practice questions and study tips. Teachers get curriculum resources and teaching strategies.

Typically responds within 24 hours
✓

Message Sent!

Thanks for reaching out. I'll get back to you within 24 hours.

🏫 Welcome, fellow educator!

I offer curriculum resources, practice materials, and study guides designed for AP CS teachers. Let me know what you're looking for — whether it's classroom materials, a guest speaker, or Teachers Pay Teachers resources.

✉

Email

[email protected]

📚

Courses

AP CSA, CSP, & Cybersecurity

⏱

Response Time

Within 24 hours

Prefer email? Reach me directly at [email protected]