The scenario describes a hybrid encryption solution based on the OpenPGP standard that uses both symmetric and asymmetric encryption. The key phrase in the question is “a free implementation of the OpenPGP standard,” which directly refers to GPG.

GPG (GNU Privacy Guard) is a free, open-source implementation of the OpenPGP standard.

It combines symmetric encryption for data encryption (fast and efficient) and asymmetric encryption for secure key exchange (using public/private key pairs).

GPG is widely used to secure emails, files, and messages, often in conjunction with tools like Thunderbird or command-line utilities.

Incorrect Options:

A. PGP (Pretty Good Privacy) is the original proprietary implementation of OpenPGP, not free/open-source by default.

B. S/MIME (Secure/Multipurpose Internet Mail Extensions) is another email encryption standard but does not implement OpenPGP.

C. SMTP (Simple Mail Transfer Protocol) is a mail transport protocol, not an encryption method.

Reference – CEH v13 Official Courseware:

Module 20: Cryptography

Section: “Hybrid Encryption and Email Encryption Tools”

Subsection: “GPG and OpenPGP-Based Encryption”

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