This CKS practice question tests your understanding of cluster setup and hardening. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
Which THREE of the following are valid encryption providers that can be used in EncryptionConfiguration for encryption at rest?
aescbc
AES-CBC is a valid encryption provider.
kms
KMS (Key Management Service) is a valid provider.
aesgcm
Why wrong: AES-GCM is not a valid provider; use aescbc or secretbox.
rsa
Why wrong: RSA is not a supported encryption provider in EncryptionConfiguration.
secretbox
Secretbox is a valid encryption provider using XSalsa20 and Poly1305.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
aescbc
Option A (aescbc) is correct because AES-CBC is a symmetric encryption algorithm that Kubernetes supports natively in EncryptionConfiguration for encrypting Secrets at rest. It uses a 32-byte key for AES-256 encryption and is the most commonly used provider for this purpose.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
aescbc
Why this is correct
AES-CBC is a valid encryption provider.
Related concept
Read the scenario before looking for a memorised answer.
kms
Why this is correct
KMS (Key Management Service) is a valid provider.
Related concept
Read the scenario before looking for a memorised answer.
aesgcm
Why it's wrong here
AES-GCM is not a valid provider; use aescbc or secretbox.
rsa
Why it's wrong here
RSA is not a supported encryption provider in EncryptionConfiguration.
secretbox
Why this is correct
Secretbox is a valid encryption provider using XSalsa20 and Poly1305.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
CNCF often tests that candidates confuse AES-GCM (which is not supported) with AES-CBC (which is supported), or assume RSA (asymmetric) can be used for at-rest encryption when Kubernetes only supports symmetric or KMS-based providers.
Detailed technical explanation
Kubernetes EncryptionConfiguration supports four providers: identity (no encryption), aescbc (AES-CBC with PKCS#7 padding), secretbox (XSalsa20-Poly1305 from NaCl/libsodium), and kms (Key Management Service, e.g., AWS KMS or GCP Cloud KMS). The aescbc provider requires a 32-byte key for AES-256, and the key is base64-encoded in the configuration file. A real-world scenario is when you need to rotate encryption keys without re-encrypting all data; Kubernetes allows key rotation by specifying multiple keys in the configuration, with the first key used for encryption and all keys tried for decryption.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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.
What to study next
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FAQ
Cluster Setup and Hardening — This question tests Cluster Setup and Hardening — Read the scenario before looking for a memorised answer..
The correct answer is: aescbc — Option A (aescbc) is correct because AES-CBC is a symmetric encryption algorithm that Kubernetes supports natively in EncryptionConfiguration for encrypting Secrets at rest. It uses a 32-byte key for AES-256 encryption and is the most commonly used provider for this purpose.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This CKS practice question is part of Courseiva's free CNCF 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 CKS exam.
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