The answer is that the application failed to include the required x-amz-server-side-encryption-customer-key header in the GET request. SSE-C mandates that every read or write request must supply both the encryption key and its MD5 checksum via specific headers; if the key header is missing or malformed, S3 rejects the request with an invalid header error because it cannot decrypt the object without that customer-provided key. On the AWS Certified Security Specialty SCS-C02 exam, this question tests your understanding that SSE-C is a header-driven encryption model where the customer manages the key entirely outside of AWS, unlike SSE-S3 or SSE-KMS. A common trap is confusing SSE-C with KMS, which uses an encryption context instead of a raw key header. Memory tip: SSE-C = Customer must Carry the key in the Call headers.
SCS-C02 Data Protection Practice Question
This SCS-C02 practice question tests your understanding of data protection. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A company uses Amazon S3 to store sensitive documents. The security policy requires that all objects be encrypted using server-side encryption with customer-provided keys (SSE-C). An application fails when trying to read an object with the error 'The request includes an invalid header.' What is the MOST likely cause?
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 application did not include the x-amz-server-side-encryption-customer-key header in the GET request.
Option A is correct because SSE-C requires the encryption key to be provided in the request headers; if the key is missing or incorrect, the request fails with an invalid header error. Option B is wrong because SSE-C does not involve KMS keys. Option C is wrong because SSE-C does not require an encryption context. Option D is wrong because SSE-C does not require bucket versioning.
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 application did not specify an encryption context in the request.
Why it's wrong here
SSE-C does not use encryption context.
✗
The KMS key used for encryption has been disabled.
Why it's wrong here
SSE-C does not use KMS.
✓
The application did not include the x-amz-server-side-encryption-customer-key header in the GET request.
Why this is correct
SSE-C requires the customer-provided key in every request.
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 S3 bucket does not have versioning enabled.
Why it's wrong here
Versioning is not required for SSE-C.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Data Protection — This question tests Data Protection — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The application did not include the x-amz-server-side-encryption-customer-key header in the GET request. — Option A is correct because SSE-C requires the encryption key to be provided in the request headers; if the key is missing or incorrect, the request fails with an invalid header error. Option B is wrong because SSE-C does not involve KMS keys. Option C is wrong because SSE-C does not require an encryption context. Option D is wrong because SSE-C does not require bucket versioning.
What should I do if I get this SCS-C02 question wrong?
Identify which SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company uses Amazon S3 to store sensitive documents. The security policy requires that all objects be encrypted with server-side encryption using customer-provided encryption keys (SSE-C). A developer uploads objects using the AWS SDK but forgets to include the encryption key in the request. What happens to the upload?
medium
A.The upload succeeds and the object is encrypted with the default S3 managed key
B.The upload succeeds and the object is encrypted with the bucket's default encryption settings
✓ C.The upload succeeds but the object is stored without server-side encryption
D.The upload fails with a 400 Bad Request error
Why C: With SSE-C, the request must include the encryption key. If not provided, the upload succeeds but the object is stored without server-side encryption (i.e., as plaintext). Option C is correct. Option A is wrong because S3 does not deny; B is wrong because no error; D is wrong because default encryption is not applied.
Last reviewed: Jun 20, 2026
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This SCS-C02 practice question is part of Courseiva's free Amazon Web Services 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 SCS-C02 exam.
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