The correct answer is "It uses an ESP for authentication and encryptio". The Encapsulating
Security Payload, (ESP) is a component of IPSec. Socket Security (SOCKS) is a transport layer,
secure networking proxy protocol. SOCKS replaces the standard network systems calls with its
own calls. These calls open connections to
a SOCKS proxy server for client authentication, transparently to the user.
Common network utilities, like TELNET or FTP, need to be SOCKSified,
or have their network calls altered to recognize SOCKS proxy calls.
Source: Designing Network Security by Merike Kaeo (Cisco Press, 1999).