Cisco PIX 525 Specifikace stáhnout pdf (Strana 572)

Glossary

GL-4

Cisco Security Appliance Command Line Configuration Guide

OL-6721-01

CTIQBE

Computer Telephony Interface Quick Buffer Encoding. A protocol used in IP telephony between the

Cisco CallManager and CTI TAPI and JTAPI applications. CTIQBE is used by the TAPI/JTAPI

protocol inspection module and supports NAT, PAT, and bi-directional NAT. This enables Cisco IP

SoftPhone and other Cisco TAPI/JTAPI applications to communicate with Cisco CallManager for call

setup and voice traffic across the security appliance.

cut-through proxy

Enables the security appliance to provide faster traffic flow after user authentication. The cut-through

proxy challenges a user initially at the application layer. After the security appliance authenticates the

user, it shifts the session flow and all traffic flows directly and quickly between the source and

destination while maintaining session state information.

data confidentiality

Describes any method that manipulates data so that no attacker can read it. This is commonly achieved

by data encryption and keys that are only available to the parties involved in the communication.

data integrity

Describes mechanisms that, through the use of encryption based on secret key or public key

algorithms, allow the recipient of a piece of protected data to verify that the data has not been modified

in transit.

data origin

authentication

A security service where the receiver can verify that protected data could have originated only from

the sender. This service requires a data integrity service plus a key distribution mechanism, where a

secret key is shared only between the sender and receiver.

decryption

Application of a specific algorithm or cipher to encrypted data so as to render the data comprehensible

to those who are authorized to see the information. See also encryption.

DES

Data encryption standard. DES was published in 1977 by the National Bureau of Standards and is a

secret key encryption scheme based on the Lucifer algorithm from IBM. Cisco uses DES in classic

crypto (40-bit and 56-bit key lengths), IPSec crypto (56-bit key), and 3DES (triple DES), which

performs encryption three times using a 56-bit key. 3DES is more secure than DES but requires more

processing for encryption and decryption. See also AES, ESP.

DHCP

Dynamic Host Configuration Protocol. Provides a mechanism for allocating IP addresses to hosts

dynamically, so that addresses can be reused when hosts no longer need them and so that mobile

computers, such as laptops, receive an IP address applicable to the LAN to which it is connected.

Diffie-Hellman

A public key cryptography protocol that allows two parties to establish a shared secret over insecure

communications channels. Diffie-Hellman is used within IKE to establish session keys.

Diffie-Hellman is a component of Oakley key exchange.

Diffie-Hellman

Group 1, Group 2,

Group 5, Group 7

Diffie-Hellman refers to a type of public key cryptography using asymmetric encryption based on

large prime numbers to establish both Phase 1 and Phase 2 SAs. Group 1 provides a smaller prime

number than Group 2 but may be the only version supported by some IPSec peers. Diffe-Hellman

Group 5 uses a 1536-bit prime number, is the most secure, and is recommended for use with AES.

Group 7 has an elliptical curve field size of 163 bits and is for use with the Movian VPN client, but

works with any peer that supports Group 7 (ECC). See also VPN and encryption.

digital certificate

See certificate.

DMZ

See interface.

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