Quick Answer
TLS 1.2 is the correct choice because it is the minimum version of Transport Layer Security approved by the PCI DSS for encrypting cardholder data over open networks, providing strong cryptography and forward secrecy that prevents decryption of past sessions even if a private key is compromised. The Payment Card Industry Data Security Standard explicitly prohibits SSL and early TLS versions like 1.0 due to known vulnerabilities such as POODLE and BEAST, making TLS 1.2 the baseline for compliance. On the CISSP exam, this question tests your understanding of cryptographic protocols within the Communication and Network Security domain, often appearing as a trap where SSL or TLS 1.0 are listed as plausible answers. A common memory tip is to remember that PCI DSS requires “TLS 1.2 or higher” — think of the number “12” as the minimum age for secure transmission.
This CISSP practice question tests your understanding of communication and network 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.
A network architect is designing a network to comply with PCI DSS requirements that cardholder data must be encrypted during transmission over open networks. Which protocol should be used for encrypting traffic between a point-of-sale (POS) terminal and the payment gateway?
TLS 1.0
Why wrong: TLS 1.0 is deprecated and not compliant with PCI DSS.
TLS 1.2
TLS 1.2 is secure and widely accepted for payment transactions.
SSH
Why wrong: SSH is for remote administration, not for POS traffic.
SSL 3.0
Why wrong: SSL 3.0 is insecure and prohibited by PCI DSS.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
TLS 1.2
TLS 1.2 is the correct choice because it is a widely accepted, secure protocol for encrypting data in transit, and it meets PCI DSS requirements for strong cryptography. PCI DSS explicitly prohibits the use of SSL and early TLS versions (1.0) due to known vulnerabilities, and TLS 1.2 provides robust cipher suites and forward secrecy.
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.
TLS 1.0
Why it's wrong here
TLS 1.0 is deprecated and not compliant with PCI DSS.
TLS 1.2
Why this is correct
TLS 1.2 is secure and widely accepted for payment transactions.
Related concept
Read the scenario before looking for a memorised answer.
SSH
Why it's wrong here
SSH is for remote administration, not for POS traffic.
SSL 3.0
Why it's wrong here
SSL 3.0 is insecure and prohibited by PCI DSS.
Common exam traps
The trap here is that candidates may confuse TLS 1.0 with TLS 1.2, assuming all TLS versions are equally secure, but PCI DSS explicitly requires TLS 1.2 or higher, and TLS 1.0 is considered weak and non-compliant.
Detailed technical explanation
TLS 1.2 uses a handshake to negotiate cipher suites, authenticate the server via X.509 certificates, and establish symmetric encryption keys using algorithms like AES-GCM. In a POS environment, the terminal typically initiates a TLS 1.2 connection to the payment gateway over TCP port 443, ensuring that cardholder data is encrypted before traversing the open network. A subtle but critical behavior is that TLS 1.2 supports forward secrecy via ephemeral Diffie-Hellman (DHE) or elliptic curve Diffie-Hellman (ECDHE), which prevents decryption of past sessions if the private key is compromised.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.
What to study next
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
Communication and Network Security — This question tests Communication and Network Security — Read the scenario before looking for a memorised answer..
The correct answer is: TLS 1.2 — TLS 1.2 is the correct choice because it is a widely accepted, secure protocol for encrypting data in transit, and it meets PCI DSS requirements for strong cryptography. PCI DSS explicitly prohibits the use of SSL and early TLS versions (1.0) due to known vulnerabilities, and TLS 1.2 provides robust cipher suites and forward secrecy.
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 24, 2026
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.
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