FileZilla Server - Download FileZilla Server 0.9.60.2 for Windows
OpenSSL - OpenSSL is a free and open source software cryptography library that implements both the Secure Sockets Layer (SSL) and the Transport Layer Security (TLS) protocols, which are primarily used to provide secure communications between web browsers and …
vsftpd - Very secure FTP Daemon, a secure, fast FTP server for UNIX systems, including Linux.
GnuTLS - GnuTLS (the GNU Transport Layer Security Library) is a free software implementation of the SSL, TLS...
Baby FTP Server - The simplest FTP server to setup. No authentication required.
mbed TLS - mbed TLS . PolarSSL . Easy to use SSL library in C . Embedded . Open source . Readable source code . Tested . Well-documented ✓