Which of the following protocols is an alternative to certificate revocation lists (CRL) and allows the authenticity of a certificate to be immediately verified?

Which of the following protocols is an alternative to certificate revocation lists (CRL) and allows the
authenticity of a certificate to be immediately verified?

A.
RSTP

B.
SKIP

C.
OCSP

D.
HTTP

Explanation:
The Online Certificate Status Protocol (OCSP) is an Internet protocol used for obtaining
the revocation status of an X.509 digital certificate. It
is described in RFC 2560 and is on the Internet standards track. It was created as an alternative to
certificate revocation lists (CRL),
specifically addressing certain problems associated with using CRLs in a public key infrastructure
(PKI). The OCSP allows the authenticity of a
certificate to be immediately verified.
Answer option A is incorrect. Rapid Spanning Tree Protocol (RSTP) is an evolution of the Spanning
Tree Protocol, which provides for faster

spanning tree convergence after a topology change. RSTP is also known as the IEEE 802.1w. It
provides a loop-free switching environment.
Standard IEEE 802.1D-2004 incorporates RSTP and obsoletes STP. While STP can take 30 to 50
seconds to respond to a topology change,
RSTP is typically able to respond to changes within 6 seconds.
Answer option D is incorrect. Hypertext Transfer Protocol (HTTP) is a client/server TCP/IP protocol
used on the World Wide Web (WWW) to
display Hypertext Markup Language (HTML) pages. HTTP defines how messages are formatted and
transmitted, and what actions Web
servers and browsers should take in response to various commands. For example, when a client
application or browser sends a request to
the server using HTTP commands, the server responds with a message containing the protocol
version, success or failure code, server
information, and body content, depending on the request. HTTP uses TCP port 80 as the default
port.
Answer option B is incorrect. SKIP (Simple Key-Management for Internet Protocol) is developed by
the IETF Security Working Group for the
sharing of encryption keys. It is used to protect sessionless datagram protocols. SKIP works at Layer 3
of the OSI model. It integrates with
the IPSec (Internet Protocol Security).