The correct answer is that the device has a lock screen PIN set, and the backup was created with default settings. This encryption occurs because Android’s Backup Manager, when invoked via ADB without specifying a password, automatically uses the device’s lock screen PIN or password as the encryption key for the resulting .ab file. This is a separate security layer from full-disk encryption, designed specifically to protect backup data during transfer or storage. On the CHFI exam, this concept tests your understanding of Android forensic acquisition methods and common pitfalls—many candidates mistakenly assume encryption implies full-disk encryption or third-party tools, but the trap is that a simple lock screen PIN triggers this default behavior. Remember the mnemonic: “Default backup, PIN locked—encryption unlocked.”
CHFI Mobile and Malware Forensics Practice Question
This CHFI practice question tests your understanding of mobile and malware forensics. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
During an Android forensic examination, an analyst uses ADB to perform a backup of a device. The resulting .ab file is encrypted. Which of the following is the most likely reason for the encryption?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The device has a lock screen PIN set, and the backup was created with default settings
When an Android backup is created via ADB with default settings, the resulting .ab file is encrypted using the device's lock screen PIN or password as the encryption key. This is a built-in security feature of the Android Backup Manager to protect backup data from unauthorized access. The encryption is applied regardless of whether full-disk encryption is enabled, as it is a separate layer of protection for the backup stream.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
The device has a lock screen PIN set, and the backup was created with default settings
Why this is correct
By default, adb backup encrypts the backup using the device's lock screen credentials.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The backup was created with the -nopassword flag
Why it's wrong here
The -nopassword flag disables encryption.
✗
The backup file is corrupted
Why it's wrong here
Corruption does not cause encryption.
✗
The device has full-disk encryption enabled
Why it's wrong here
Full-disk encryption encrypts the entire storage, but ADB backup encryption is independent and uses lock screen credentials.
Common exam traps
Common exam trap: answer the scenario, not the keyword
EC-Council often tests the distinction between full-disk encryption and backup-level encryption, leading candidates to incorrectly assume that FDE is the cause of the encrypted .ab file when the real mechanism is the lock screen PIN used by the Android Backup Manager.
Detailed technical explanation
How to think about this question
The ADB backup command (adb backup -f backup.ab) creates a backup in Android Backup format, which uses a header containing encryption parameters (e.g., AES-256-CBC with a PBKDF2-derived key). The encryption key is derived from the user's lock screen PIN/password, not from the device's FDE key. In practice, even if FDE is enabled, the backup file can still be decrypted by providing the correct lock screen credential, making it a critical forensic artifact.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CHFI question in full detail.
Mobile and Malware Forensics — This question tests Mobile and Malware Forensics — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The device has a lock screen PIN set, and the backup was created with default settings — When an Android backup is created via ADB with default settings, the resulting .ab file is encrypted using the device's lock screen PIN or password as the encryption key. This is a built-in security feature of the Android Backup Manager to protect backup data from unauthorized access. The encryption is applied regardless of whether full-disk encryption is enabled, as it is a separate layer of protection for the backup stream.
What should I do if I get this CHFI question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This CHFI practice question is part of Courseiva's free EC-Council 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 CHFI exam.
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