Stunnel

Stunnel is a utility that adds SSL encryption to various daemons and servers, such as POP2, POP3, IMAP, NNTP, SMTP, and HTTP, using the OpenSSL library. It supports multiple cryptographic algorithms and can incorporate FIPS 140-2 validated encryption through the OpenSSL FIPS Provider, included in the Windows installer. This makes Stunnel a powerful tool for enhancing security across platforms, ensuring data protection and compliance for both legacy and modern network services.