User Guide

624 Glossary
320657-A
The PKI uses the digital certificate to identify an individual or an organization. The private key is given only
to the requesting party and is never shared, and the public key is made publicly available (as part of the digital
certificate) in a directory that all parties can access. You use the private key to decrypt text that has been
encrypted with your public key by someone else. The certificates are stored (and, when necessary, revoked) by
directory services and managed by a certificate management system. See also certificate authority (CA);
registration authority (RA).
plenum A compartment or chamber to which one or more air ducts are connected.
plenum-rated cable A type of cable approved by an independent test laboratory for installation in
ducts, plenums, and other air-handling spaces.
PMK Pairwise master key. A code derived from a master secret and used as an encryption key for IEEE
802.11 encryption algorithms. A PMK is also used to derive a pairwise transient key (PTK) for IEEE 802.11i
robust security. See also master secret; PTK.
PoE Power over Ethernet. A technology, defined in the developing IEEE 802.3af standard, to deliver DC
power over twisted-pair Ethernet data cables rather than power cords. The electrical current, which enters the
data cable at the power-supply end and comes out at the device end, is kept separate from the data signal so
neither interferes with the other.
policy A formal set of statements that define the way a network’s resources are allocated among its
clients—individual users, departments, host computers, or applications. Resources are statically or
dynamically allocated by such factors as time of day, client authorization priorities, and availability of
resources.
Policy Manager A WLAN Management Software feature that allows you to apply a collection of
configuration settings known as a domain policy, or part of the policy, to one or more WLAN—Security
Switch (WSS) switches. With Policy Manager, you can also merge some or all of the configuration changes
you make to a single WSS switch into a domain policy. See also domain policy.
port address translation See PAT.
Power over Ethernet See PoE.
pre-master secret A key generated during the handshake process in Transport Layer Security (TLS)
protocol negotiations and used to derive a master secret.
preshared key See PSK.
PRF Pseudorandom function. A function that produces effectively unpredictable output. A PRF can use
multiple iterations of one or more hash algorithms to achieve its output. The Transport Layer Security (TLS)
protocol defines a specific PRF for deriving keying material.
Privacy-Enhanced Mail See PEM.
private key In cryptography, one of a pair of keys, one public and one private, that are created with the
same algorithm for encrypting and decrypting messages and digital signatures. The private key is provided to
only the requestor and never shared. The requestor uses the private key to decrypt text that has been encrypted
with the public key by someone else. See also PKI; public key.
PRNG Pseudorandom number generator. An algorithm of predictable behavior that generates a sequence of
numbers with little or no discernible order, except for broad statistical patterns.