Rivest, Shamir, and Adleman (RSA) Invented by Ron Rivest, Adi Shamir, and Len Adleman in 1977, RSA is one of the most common asymmetric algorithms in use today. This public-keyalgorithm was patented until September 2000, when the patent expired, making the algorithm part of the public domain. RSA has been widely embraced over the years, in part because of its ease of implementation and its flexibility.

role-based command-line interface (CLI) views Can be used to provide different sets of configuration information to different administrators. However, unlike making commands available via privilege levels, using role-based CLI views you can control exactly what commands an administrator has access to.

RTP Control Protocol (RTCP) Provides information about an RTP flow, such as information about the quality of the call. In a Cisco environment, RTCP typically uses odd-numbered UDP ports in the range 16,384 to 32,767.

salami attack A collection of small attacks that result in a larger attack when combined.

salt A series of random bits added to a password. When the password is hashed, and that hash is stored in a database, two identical passwords do not create the same hash. This also protects the passwords from attacks involving rainbow tables.

Secure RTP (SRTP) Secures the transmission of voice via Real-time Transport Protocol (RTP). Specifically, SRTP adds encryption, authentication, integrity, and antireplay mechanisms to voice traffic.

Secure Shell (SSH) A protocol that provides encryption and authentication functions for remote terminal sessions. This allows an administrator to securely attach to and exchange information with a router, for example. Cisco recommends that SSH be used instead of Telnet because Telnet sends data in plain text.

Security level Defines the type of security algorithm performed on SNMP packets. Examples of security levels are noAuthNoPriv, authNoPriv, and authPriv.

Security model Defines an approach for user and group authentication. Cisco IOS supports the SNMPv1, SNMPv2c, and SNMPv3 security models.

Security policy A continually changing document that dictates a set of guidelines for network use. These guidelines complement organizational objectives by specifying rules for how the network is used.