Remember CTR
Full name: Counter mode
Memory aid: CounTeRs produce a changing keystream.
Counter-mode encryption alone does not detect intentional modification.
Study area: Cryptography & trust · Batch 8
Relevant study for: CompTIA Security+ SY0-701 · ISC2 CISSP 2024 outline · ISC2 SSCP · CompTIA SecurityX · Cybersecurity Architect SC-100 · ISC2 CCSP · Security, Compliance, and Identity Fundamentals SC-900
Practice with exam flashcards →Cybersecurity & Identity / Knowledge library
CTR — Counter mode
Builds a stream-like encryption construction by encrypting counter blocks.
Why learn CTR — Counter mode?
Builds a stream-like encryption construction by encrypting counter blocks.
Where it came from
Counter-mode encryption alone does not detect intentional modification.
- Memory aid (a learning cue, not the expansion): CounTeRs produce a changing keystream.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Without looking, expand CTR: Counter mode.
- Recall this memory aid: CounTeRs produce a changing keystream.
- Explain the practical use: Builds a stream-like encryption construction by encrypting counter blocks.
- Explain this distinction: Counter-mode encryption alone does not detect intentional modification.
- Identify CTR in a device specification, architecture diagram, or system inventory.
Documentation and sources
- NIST block cipher modes (csrc.nist.gov)