Symantec 10521146 - Network Security 7120 Administration Manual page 356

356 Glossary
private key
probe
protocol
Protocol Anomaly
Detection
proxy server
public key
public key cryptography A cryptographic system in which two different keys are used for encryption and
QoS (quality of service) The idea that transmission rates, error rates, and other characteristics on the Internet and
A part of asymmetric encryption that uses a private key in conjunction with a public key.
The private key is kept secret, while the public key is sent to those with whom a user
expects to communicate. The private key is then used to encrypt the data, and the
corresponding public key is used to decrypt it. The risk in this system is that if either party
loses the key or the key is stolen, the system is broken.
An effort, such as a request, transaction, or program, that is used to gather information
about a computer or the state of a network. For example, sending an empty message to see
whether a destination actually exists. Ping is a common utility for sending such a probe.
Some probes are inserted near key junctures in a network for the purpose of monitoring or
collecting data about network activity.
A set of rules for encoding and decoding data so that messages can be exchanged between
computers and so that each computer can fully understand the meaning of the messages.
On the Internet, the exchange of information between different computers is made
possible by the suite of protocols known as TCP/IP. Protocols can be stacked, meaning that
one transmission can use two or more protocols. For example, an FTP session uses the FTP
protocol to transfer files, the TCP protocol to manage connections, and the IP protocol to
deliver data.
One of an array of methodologies by which Symantec Network Security inspects network
traffic, compares observed behavior during network protocol exchange to structured
protocols, analyzes defiant behavior in context, and detects deviations from the norm.
A server that acts on behalf of one or more other servers, usually for screening, firewall, or
caching purposes, or a combination of these purposes. Also called a gateway. Typically, a
proxy server is used within a company or enterprise to gather all Internet requests,
forward them out to Internet servers, and then receive the responses and in turn forward
them to the original requester within the company.
A part of asymmetric encryption that operates in conjunction with the private key. The
sender looks up the public key of the intended recipient and uses the public key to encrypt
the message. The recipient then uses his or her private key, which is not made public, to
decrypt the message.
decryption. Also called asymmetric cryptography. The sender of the message looks up the
public key of the intended recipient and uses the public key to encrypt the message. The
recipient then uses his or her private key, which is not made public to decrypt the
message. This method of encryption is considered more secure than symmetrical
cryptography because one of the keys is kept strictly private.
in other networks, can be measured, improved, and, to some extent, guaranteed in
advance. QoS is of particular concern for the continuous transmission of high-bandwidth
video and multimedia information.