A person approaches a network administrator and wants advice on how to send encrypted email from home. The end user does not want to have to pay for any license fees or manage server services. Which o

IPSec operates at the network layer to secure IP traffic between hosts or networks, and is not an email encryption protocol.

MIME (and its extension S/MIME) is primarily a format standard for structuring email with attachments; basic MIME provides no encryption, and S/MIME requires a certificate authority and managed certificates.

PGP (and its open-source implementation GPG) uses asymmetric public-key cryptography to encrypt email content end-to-end, meaning only the intended recipient can decrypt the message. It requires no license fees and no server infrastructure - users exchange public keys directly - making it perfectly suited to the home user's requirements while providing strong, standards-based encryption (defined in RFC 4880).

HTTPS is a web transport protocol for securing browser-to-server communication and does not encrypt email messages stored or transmitted via mail protocols such as SMTP or IMAP.