CISSP Asset Security Practice Question
An organization uses full disk encryption on all laptops containing sensitive data. A laptop is to be decommissioned, and the data must be sanitized. The laptop's SSD cannot be overwritten reliably due to wear-leveling. Which method is most appropriate?
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
✓
Cryptographic erasure by destroying the encryption key
Cryptographic erasure (destroying the encryption key) renders data inaccessible if encryption is strong, suitable for SSDs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Degaussing
Why it's wrong here
Degaussing is a data sanitization method specifically designed for magnetic storage media, such as traditional hard disk drives (HDDs) and magnetic tapes. It works by exposing the media to a powerful magnetic field, which randomizes the magnetic domains that store data, effectively erasing the information. However, Solid State Drives (SSDs) store data using electrical charges in NAND flash memory cells, not magnetic properties, rendering degaussing completely ineffective against them.
- ✗
DoD 5220.22-M 7-pass overwrite
Why it's wrong here
The DoD 5220.22-M standard, including its 7-pass overwrite method, was developed for traditional magnetic hard disk drives where data is written directly to specific physical sectors. For Solid State Drives (SSDs), this method is largely ineffective due to their internal wear-leveling algorithms and over-provisioning. The SSD controller actively remaps logical block addresses to different physical NAND flash memory blocks to extend device lifespan, meaning a software-based overwrite may not target all existing data blocks, leaving residual data recoverable.
- ✓
Cryptographic erasure by destroying the encryption key
Why this is correct
Cryptographic erasure is the most appropriate and highly effective method for sanitizing data on encrypted Solid State Drives (SSDs). When full disk encryption (FDE) is employed, all data on the drive is rendered unreadable without the correct encryption key. By securely destroying or invalidating this master encryption key, all data on the drive becomes cryptographically inaccessible and irrecoverable, effectively sanitizing the media without physically altering the drive itself. This method is fast, efficient, and allows for device reuse.
- ✗
Physical destruction (shredding)
Why it's wrong here
Physical destruction, such as shredding, pulverizing, or incineration, is an undeniably effective method for data sanitization as it completely destroys the storage medium, making data recovery impossible. While highly secure, this method is irreversible and prevents any future reuse of the device or its components. Therefore, it is generally considered an extreme measure and not the most appropriate choice if the goal is to securely sanitize data while retaining the functional integrity of the laptop for potential redeployment or resale.
Go deeper
Related to this question
Learn chapter
Asset Security: Privacy and Data Retention
Key term
Disk encryption
Disk encryption is the process of converting data on a storage device into a coded form that can only be read with the correct decryption key, protecting it from unauthorized access.
Key term
Encryption
Encryption is the process of converting readable data into a secret code to prevent unauthorized access.
About these practice questions
One of 747 original CISSP practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.