Glossary of Key Information Security Terms (NIST) part 49 / P -Q -R

Pseudorandom number generator – (PRNG)

An algorithm that produces a sequence of bits that are uniquely determined from an initial value called a seed. The output of the PRNG “appears” to be random, i.e., the output is statistically indistinguishable from random values. A cryptographic PRNG has the additional property that the output is unpredictable, given that the seed is not known.

Pseudonym –

A false name. 1. A subscriber name that has been chosen by the subscriber that is not verified as meaningful by identity proofing. 2. An assigned identity that is used to protect an individual’s true identity.

Public Domain Software –

Software not protected by copyright laws of any nation that may be freely used without permission of, or payment to, the creator, and that carries no warranties from, or liabilities to the creator.

Purge –

Rendering sanitized data unrecoverable by laboratory attack methods.

Quadrant –

Short name referring to technology that provides tamper-resistant protection to cryptographic equipment.

Qualitative Assessment –

Use of a set of methods, principles, or rules for assessing risk based on nonnumeric categories or levels.

Quality of Service –

The measurable end-to-end performance properties of a network service, which can be guaranteed in advance by a Service-Level Agreement between a user and a service provider, so as to satisfy specific customer application requirements. Note: These properties may include throughput (bandwidth), transit delay (latency), error rates, priority, security, packet loss, packet jitter, etc.

Quantitative Assessment –

Use of a set of methods, principles, or rules for assessing risks based on the use of numbers where the meanings and proportionality of values are maintained inside and outside the context of the assessment.

Quarantine –

Store files containing malware in isolation for future disinfection or examination.

Radio Frequency Identification – (RFID)

A form of automatic identification and data capture (AIDC) that uses electric or magnetic fields at radio frequencies to transmit information.

Random Bit Generator (RBG) –

A device or algorithm that outputs a sequence of binary bits that appears to be statistically independent and unbiased. An RBG is either a DRBG or an NRBG.

Random Number Generator – (RNG)

A process used to generate an unpredictable series of numbers. Each individual value is called random if each of the values in the total population of values has an equal probability of being selected.

Random Number Generator – (RNG)

Random Number Generators (RNGs) used for cryptographic applications typically produce a sequence of zero and one bits that may be combined into sub-sequences or blocks of random numbers. There are two basic classes: deterministic and nondeterministic. A deterministic RNG consists of an algorithm that produces a sequence of bits from an initial value called a seed. A nondeterministic RNG produces output that is dependent on some unpredictable physical source that is outside human control.

Randomizer –

Analog or digital source of unpredictable, unbiased, and usually independent bits. Randomizers can be used for several different functions, including key generation or to provide a starting state for a key generator.

RBAC –

See Role-Based Access Control.

Read –

Fundamental operation in an information system that results only in the flow of information from an object to a subject.

Read Access –

Permission to read information in an information system.

Real-Time Reaction –

Immediate response to a penetration attempt that is detected and diagnosed in time to prevent access.

Recipient Usage Period –

The period of time during the cryptoperiod of a symmetric key when protected information is processed.

Reciprocity –

Mutual agreement among participating enterprises to accept each other’s security assessments in order to reuse information system resources and/or to accept each other’s assessed security posture in order to share information. Mutual agreement among participating organizations to accept each other’s security assessments in order to reuse information system resources and/or to accept each other’s assessed security posture in order to share information.