Multi-Tech Systems RF600, RF660, RF760 - page 177

Glossary
Multi-Tech Systems, Inc. RouteFinderVPN RF760/660/600VPN User Guide (PN S000323D) 177
CSS (Cascading Style Sheets) – HTML was intended to mark up only a Web page's structure, but not its on-screen display
characteristics. For Web page appearances, the World Wide Web Consortium (W3C) developed a complementary markup
system called Cascading Style Sheets (CSS) to make it easier to define a page's appearance without affecting its HTML
structure. HTML can be frustrating when trying to control the appearance of a Web page and its contents. Style sheets work
like templates: you define the style for a particular HTML element once, and then use it over and over on any number of Web
pages. To change how an element looks, you just change the style; the element automatically changes wherever it appears.
(Before CSS, you had to change the element individually, each time it appeared.) Style sheets let Web designers more
quickly create consistent pages and more consistent web sites.
Browsers began supporting the first CSS Specification, Cascading Style Sheets, Level 1 (CSS1), in versions 3.0 of Opera
and Microsoft Internet Explorer and in version 4.0 of Netscape Navigator. The 4.0 and later versions of all three browsers
also support properties from the newer Cascading Style Sheets, Level 2 (CSS2) specification, which let you specify
elements' visibilities, their precise positions on the page, and how they overlap each other.
Certificate – A cryptographically signed object that contains an identity and a public key associated with the identity. Public
key certificates are digital stamps of approval for electronic security. The three main characteristics of certificates are 1)
provide identification of the web site and the owner, 2) contain the public key to be used to encrypt and decrypt messages
between parties, and 3) provide a digital signature from the trusted organization that issued the certificate, as well as when
the certificate expires.
Certificate Authority – The issuer of a certificate is the Certificate Authority (CA). The CA is the party that digitally signs a
certificate and ensures its validity. There are two types of CAs, private and public. Private CAs issue certificates for use in
private networks where they can validate the certificate. Public CAs issues certificates for servers that belong to the general
public. A Public CA must meet certain requirements before they are added as a root authority to a browser. Since this is a
controlled process, all public CA must be registered to issue certificates.
Certificate Revocation List – A log of certificates that have been revoked before their expiration date.
Cipher – An encryption/decryption algorithm.
Ciphertext – Encrypted data.
Client-Server Model – A common way to describe the paradigm of many network protocols. Examples include the name-
server/name-resolver relationship in DNS and the file-server/file-client relationship in NFS.
CHAP (Challenge Handshake Authentication Protocol) – An IETF standard for authentication using PPP which uses a
"random Challenge", with a cryptographically hashed "Response" which depends on the Challenge and a secret key.
Client – A client is a program that communicates with a server via a network, so as to use the service provided by that
server. Example: Netscape is a www client, with the help of which one can call up information from a www server.
Client-Server Principle – Applications based on the client-server principle use a client program (client) at the user-end that
exchanges information with a server on the network. Usually the server is responsible for the data keeping, while the client
takes over the presentation of this information and the interaction with the user. For this, the server and the client employ an
exactly defined protocol. All the important applications in the Internet (e.g. www, FTP, news) are based on the client-server
principle.
CMP (Certificate Management Protocol) – A protocol defining the online interactions between the end entities and the
certification authority in PKI. It is written by PKIX working group of IETF and is specified in document RFC 2510.
Compromise – The unintended disclosure or discovery of a cryptographic key or secret.
CRL – Certificate Revocation List.
Cryptography – The art and science of using mathematics to secure information and create a high degree of trust in the
networking realm. See also public key, secret key.
CSR (Certificate Signing Request) – The form used to obtain a certificate from a CA. A CSR generates a formatted
certification. This request is located on the web site of all certificate authorities. Another way to generate a CSR is to use a
utility such as Microsoft IIS or OpenSSL.
Datagram – The unit of transmission at the ISO Network layer (such as IP). A datagram may be encapsulated in one or
more packets passed to the data link layer. A datagram is a self-contained, independent entity of data carrying sufficient
information to be routed from the source to the destination computer without reliance on earlier exchanges between this
source and destination computer and the transporting network.
CefaultRoute – A routing table entry that is used to direct packets addressed to networks not explicitly listed in the routing
table.
DES (Data Encryption Standard) – A secret key encryption scheme; contrast with “public key”. DES is an NIST standard
for a secret key cryptography method that uses a 56-bit key.