What type of algorithm uses the same key to encrypt and decrypt data?
A. a symmetric algorithm
B. an asymetric algorithm
C. a Public Key infrastructure algorithm
D. an IP Security algorithm
What type of algorithm uses the same key to encrypt and decrypt data?
The correct answer is A:
Symmetric Algorithms
As mentioned previously, a symmetric encryption algorithm, also known as a symmetric
cipher, uses the same key to encrypt the data and decrypt the data. Two devices
connected via a VPN both need the key (or keys) to successfully encrypt and decrypt the
data protected using a symmetric encryption algorithm.
Official Cert Guide page 436
IPS in Promiscuos Mode
-> Promiscuous mode—When running in promiscuous mode, the IPS cannot implement Deny actions.
Thus, if you want to prevent traffic from a host, you must implement blocking.
-> Inline mode—In inline mode, you can implement Deny actions to immediately drop undesired
traffic. However, you might want to add blocking actions to protect other segments of your network.
There are three types of blocks:
Host block
Connection block
Network block
Do not confuse blocking with the ability of the sensor to drop packets. The sensor can drop packets when the following actions are configured for a sensor in inline mode: deny packet inline, deny connection inline, and deny attacker inline.
FROM CISCO: https://www.cisco.com/c/en/us/td/docs/security/security_management/cisco_security_manager/security_manager/4-1/user/guide/CSMUserGuide_wrapper/ipsblock.pdf
The Attack Response Controller (ARC) component of the IPS is responsible for managing network devices in response to suspicious events by blocking access from attacking hosts and networks
ARC is formerly known as Network Access Controller. Although the name has been changed, the IPS documentation and configuration interfaces contain references to Network Access Controller, nac, and network-access.
More in:http://www.ciscopress.com/articles/article.asp?p=1336425