CISSP Security Architecture and Engineering Practice Question
Which type of covert channel uses the timing of events or operations to transmit information?
⚠ Common exam trap
CISSP often tests the distinction between storage and timing covert channels — candidates pick 'side channel' because it sounds broader, but the question asks for the specific type defined by timing.
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
✓
Timing channel
A timing channel is a covert channel that conveys information by modulating the timing of events or operations — for example, varying the delay between packets or CPU bursts so a receiver can decode bits from the timing pattern. It is a type of side channel where the shared resource is time itself.
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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Emanations channel
Why it's wrong here
An emanations channel exploits unintentional electromagnetic or acoustic emissions from computing devices to leak sensitive data. These channels rely on physical phenomena, such as radio frequency leakage from unshielded cables or sound waves from CPU activity, rather than manipulating the temporal sequence or duration of system events. Therefore, it does not align with the question's focus on event timing.
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Side channel
Why it's wrong here
A side channel is a general category of attack that extracts information from the physical implementation of a cryptosystem or other secure computation, rather than attacking the algorithm directly. While timing channels are indeed a type of side channel, the question specifically describes the mechanism of using event timing, making "timing channel" the more precise and accurate answer for the described scenario.
- ✓
Timing channel
Why this is correct
A timing channel is a specific type of covert channel that modulates information by altering the temporal characteristics of system events or operations. This involves varying the time taken for a process to complete, the delay between two events, or the order of operations, to encode and transmit data between processes that are not supposed to communicate directly. The receiver deciphers the secret message by observing these temporal variations.
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Storage channel
Why it's wrong here
A storage channel is a covert communication method that relies on the ability of one process to write information to a shared storage location and another process to read it. This typically involves manipulating shared resources like files, memory locations, or semaphores to encode data, rather than exploiting the temporal relationships or execution durations of system operations. Therefore, it does not utilize the timing of events as its primary mechanism.
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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 CISSP 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 CISSP exam.