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CAS-002 · Question #658

A developer is coding the crypto routine of an application that will be installed on a standard headless and diskless server connected to a NAS housed in the datacenter. The developer has written…

The correct answer is D. 6 and 4. On a headless, diskless server connected to a NAS, only network and keyboard inputs are realistically present, making those the only lines that will execute and contribute entropy.

Technical Integration of Enterprise Components

Question

A developer is coding the crypto routine of an application that will be installed on a standard headless and diskless server connected to a NAS housed in the datacenter. The developer has written the following six lines of code to add entropy to the routine:

1 - If VIDEO input exists, use video data for entropy 2 - If AUDIO input exists, use audio data for entropy 3 - If MOUSE input exists, use mouse data for entropy 4 - IF KEYBOARD input exists, use keyboard data for entropy 5 - IF IDE input exists, use IDE data for entropy 6 - IF NETWORK input exists, use network data for entropy Which of the following lines of code will result in the STRONGEST seed when combined?

Options

  • A2 and 1
  • B3 and 5
  • C5 and 2
  • D6 and 4

How the community answered

(22 responses)
  • A
    5% (1)
  • B
    14% (3)
  • C
    23% (5)
  • D
    59% (13)

Why each option

On a headless, diskless server connected to a NAS, only network and keyboard inputs are realistically present, making those the only lines that will execute and contribute entropy.

A2 and 1

Lines 2 and 1 require audio and video hardware respectively, both of which are absent on a headless server, so neither condition will be true and no entropy will be collected.

B3 and 5

Line 3 requires a mouse (absent on a headless server) and line 5 requires an IDE drive (absent on a diskless server), so both conditions evaluate false and no entropy is gathered.

C5 and 2

Line 5 requires an IDE drive (absent on a diskless server) and line 2 requires audio hardware (absent on a headless server), so neither contributes any entropy to the seed.

D6 and 4Correct

A headless server lacks video, audio, and mouse peripherals, so lines 1, 2, and 3 will never execute. A diskless server has no IDE drive, so line 5 will not execute either. Line 6 (NETWORK) will execute because the server communicates with the NAS, and line 4 (KEYBOARD) may execute if a keyboard is attached; together, unpredictable network traffic timing and keyboard event timing provide the highest-quality entropy available on this hardware configuration.

Concept tested: Entropy source selection for cryptographic seed generation

Source: https://csrc.nist.gov/glossary/term/entropy

Topics

#cryptographic entropy#headless server#random number generation#cryptography

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