- A
openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -days 365 -nodes
Generates key and certificate in one command.
- B
openssl genrsa -out key.pem 2048
Why wrong: Only generates a key, not a certificate.
- C
openssl req -new -x509 -days 365 -key key.pem -out cert.pem
Why wrong: Requires an existing key.
- D
openssl x509 -req -in req.pem -signkey key.pem -out cert.pem
Why wrong: Requires a CSR.
Question 376 of 1,000
XK0-005 Security Practice Question
This XK0-005 practice question tests your understanding of security. 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.
An administrator wants to generate a self-signed certificate and private key for testing. Which command creates both in one step?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"which command"Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
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
✓
openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -days 365 -nodes
Option A is correct because the `openssl req -x509 -newkey rsa:2048` command generates a new private key (via `-newkey`) and immediately creates a self-signed X.509 certificate (via `-x509`) in a single step. The `-keyout` and `-out` flags specify the output files for the private key and certificate, respectively, and `-nodes` ensures the private key is not encrypted with a passphrase, which is typical for testing scenarios.
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.
- ✓
openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -days 365 -nodes
Why this is correct
Generates key and certificate in one command.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
openssl genrsa -out key.pem 2048
Why it's wrong here
Only generates a key, not a certificate.
- ✗
openssl req -new -x509 -days 365 -key key.pem -out cert.pem
Why it's wrong here
Requires an existing key.
- ✗
openssl x509 -req -in req.pem -signkey key.pem -out cert.pem
Why it's wrong here
Requires a CSR.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse `openssl req -new` (which creates a CSR) with `openssl req -x509` (which creates a self-signed certificate), leading them to pick option C, which requires a pre-existing key and does not generate both in one step.
Detailed technical explanation
How to think about this question
The `-newkey` option in `openssl req` generates a new private key of the specified algorithm and size (e.g., RSA 2048) before creating the certificate, combining two operations that are normally separate. The `-x509` flag bypasses the CSR generation step and directly outputs a self-signed certificate, which is useful for internal testing or development environments where a trusted CA is not needed. Under the hood, OpenSSL creates a random key pair, builds a certificate with default subject fields, and signs it using the private key, all within a single invocation.
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 practitioner preparing for the XK0-005 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this XK0-005 question test?
Security — This question tests Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -days 365 -nodes — Option A is correct because the `openssl req -x509 -newkey rsa:2048` command generates a new private key (via `-newkey`) and immediately creates a self-signed X.509 certificate (via `-x509`) in a single step. The `-keyout` and `-out` flags specify the output files for the private key and certificate, respectively, and `-nodes` ensures the private key is not encrypted with a passphrase, which is typical for testing scenarios.
What should I do if I get this XK0-005 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: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jul 4, 2026
This XK0-005 practice question is part of Courseiva's free CompTIA 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 XK0-005 exam.
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