Which of the following is a version of netcat with integrated transport encryption capabilities?

Encat is not a recognized or documented network security tool - it is a fabricated option.

Nikto is an open-source web server scanner used to detect dangerous files, outdated software, and misconfigurations - it is not related to netcat or transport encryption.

Socat (SOcket CAT) is a relay tool that can proxy bidirectional data streams between various endpoints but is a separate utility from netcat and is not specifically a version of netcat with integrated encryption.

Cryptcat extends the functionality of netcat by incorporating the Twofish symmetric encryption algorithm to secure data transmitted over its connections. Unlike standard netcat, which sends data in plaintext, Cryptcat encrypts the transport layer, making it suitable for secure communications and commonly referenced in security and penetration testing contexts. It is a well-known tool in the security community specifically identified by its encryption capability over netcat.