ccna before security+

ccna before security+.7.4.5 PKI Standards7.4.5.1 Interoperability of Different PKI VendorsStandardization and interoperability of different PKI vendors remains an issue when interconnecting PKI Interoperability between PKI and its supported services, such as the Lightweight Directory Access Protocol (LDAP) and X.500 directory, is still a concern because many vendors have already developed and implemented private solutions without waiting for the development of out-of-standards. The current state of interoperability is still low, although PKI software has been in development for over 10 years.To address interoperability issues, the IETF established the Public-KeyInfrastructureX.509 (PKIX) working group to promote and standardize PKI in the Internet. The working group has published a set of draft standards (X.509) that describe in detail the common data formats and protocols related to PKI in the Web.7.4.5.2 X.509 StandardX.509 is a well-known standard that defines the basic PKI formats for achieving basic interoperability, such as the format of certificates and CertificateRevocationLists (CRLs). This standard has been in widespread use for several years with a variety of Internet applications such as SSL and IPSec.The X.509 version 3 (X.509v3) standard defines a format for digital certificates. The traditional use of certificates is to provide strong authentication for applications at the application layer. The actual authentication process used by each application can have different implementations, but they all use a similar certificate in the X.509 format.The X.509 format is already widely used in the Internet infrastructure.Secure Web servers use X.509v3 for Web site authentication in the SSL and TLS protocols.Web browsers use X.509v3 to implement HTTPS client certificates in the SSL protocol. SSL is the most widely used certificate based authentication. Other well-known applications, such as Simple Mail Transfer Protocol (SMTP) > Lightweight Directory Access Protocol (LDAP) and Post Office Protocol version 3 (POST), use weaker authentication and no encryption. PostOffice Protocolversion 3 (POP3). All have been improved to use SSLo