Glossary
GL-8
Cisco Router and Security Device Manager 2.5 User’s Guide
OL-4015-12
crypto map In Cisco SDM, crypto maps specify which traffic should be protected by IPSec,
where IPSec-protected traffic should be sent, and what IPSec transform set s
should be applied to this traffic.
cTCP Cisco Tunneling Control Protocol. cTCP is also called TCP over IPSec, or TCP
traversal. cTCP is a protocol that encapsulates ESP and IKE traffic in the TCP
header, so that firewalls in between the client and th e server or headend device
permit this traffic, considering it as TCP traffic.
D
data confidentiality The result of data encryption that prevents the disclosure of information to
unauthorized individuals, entities, or processes. This information can be either
data at the application level, or communication parameters. See traffic flow
confidentiality or traffic analysis.
data integrity The presumed accuracy of transmitted data — signifying the send er’s
authenticity and the absence of data tampering.
data origin
authentication
One function of a non-repudiation service.
decryption Reverse application of an encryption algorithm to encrypted data, thereby
restoring that data to its original, unencrypted state.
default gateway The gateway of last resort. The gateway to which a packet is routed when its
destination address does not match any entries in the routing table.
delta file A file that Cisco IOS IPS creates to store changes made to signatures.
DES Data Encryption Standard. Standard cryptographic algorithm developed and
standardized by the U.S. National Institute of Standards and Technology (NIST).
Uses a secret 56-bit encryption key. The DES algorithm is included in many
encryption standards.
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.