Which of the following is least likely used to encrypt data in a VPN connection? (Wentz QOTD)
A. TLS/SSL
B. Secure Shell (SSH)
C. IPsec
D. L2TP

Kindly be reminded that the suggested answer is for your reference only. It doesn’t matter whether you have the right or wrong answer. What really matters is your reasoning process and justifications.

My suggested answer is D. L2TP.

Wentz’s book, The Effective CISSP: Security and Risk Management, helps CISSP and CISM aspirants build a solid conceptual security model. It is a tutorial for information security and a supplement to the official study guides for the CISSP and CISM exams and an informative reference for security professionals.

VPN is a virtual network that connects nodes through tunnels. L2F, PPTP, and L2TP are early tunneling protocols. Data transmitted over VPN tunnels are typically encrypted by security protocols, such as SSL/TLS, IPsec, SSH, MPPE.

L2F doesn’t provide encryption. PPTP encrypts data using MPPE (Microsoft Point-to-Point Encryption). L2TP itself builds tunnels but doesn’t encrypt data; it typically enforces confidentiality through IPsec.

“Secure Shell (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network.” (Wikipedia) It can be used to establish SSH VPN or work with other tunneling protocols.

Reference

• NIST SP 800-77 R1
• NIST SP 800-113
• How to configure port forwarding with SSH
• HOW TO FIND SSH TUNNEL

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以下哪項最不可能用於加密 VPN 連接中的數據？ (Wentz QOTD)
A. TLS/SSL
B. Secure Shell (SSH)
C. IPsec
D. L2TP