Glossary

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

Glossary terms and definitions last updated: March 19, 2025

This Glossary is an aggregation of terms and definitions specified in NIST's cybersecurity and privacy standards, guidelines, and other technical publications, and in CNSSI 4009. These should not be viewed as "official" or "preferred" definitions for a particular subject area, sector, or industry, with the exception that some definitions are cited directly from U.S. laws, the Code of Federal Regulations, Presidential Directives, etc.

Each term-definition pair must be understood within the context of its Source document, to which readers should refer. Because of this, many terms have multiple, varying definitions that reflect the different contexts of various publications written at different times.

Cite the source publication, not this website. As our documents are published and withdrawn, the terminology on these web pages will change. When citing terms and definitions, we encourage you to cite the source publication for the authoritative terminology and to understand it in its proper context. Many terms on this website have different definitions, from multiple publications.
Public input. We invite public comments—including terminology suggestions—on our draft publications and welcome your contributions.
Artificial Intelligence (AI) terminology. For AI-focused terminology, see the Glossary available from the NIST Trustworthy & Responsible AI Resource Center.

For more background about this Glossary, see NISTIR 7298 Rev. 3.
Download the Glossary in JSON format (updated daily at 6:15 pm ET; see metadata).

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

Showing 1102 matching records.

S&RM

S/MIME

S/MIME Certificate Association (Resource Record)

S/RTBH

S_XMSS

SA&A

SaaS

SABI

SAC

SACM

SAD

SAE

SAE International

Safe Harbor

SAFECode

safeguards

SAFER

safety

Safety Instrumented Function

safety instrumented system

Safety Requirements

Safety, Controls, Alarms, and Interlocks

SAISO

SAKA

salt

SAM

SAMATE

SAML

SAML SSO

SAMM

Sample

sampling

SAN

Sandbox

sanitization

sanitize

SANITIZE Command

SANS

SAO

SAOP

SAORM

SAP

SAPF

SAR

Sarbanes-Oxley Act

SARD

SAS

SASE

SAST

SATA

SATE

satellite

Satisfaction

SAV

SBA

SBH

SBIR

SBOM

S-box

SBU

SC 37

SCA

SCADA

SCADA Security Scientific Symposium

SCADA server

SCADS

SCAI

Scalability

Scalability testing

scanning

SCAP

SCAP Capability

SCAP component

SCAP conformant

SCAP content

SCAP Content Checklist

SCAP Content Validation Tool

SCAP data stream

SCAP data stream collection

SCAP result data stream

SCAP Revision

SCAP source data stream

SCAP source data stream collection

SCAP use case

SCAPVal

SCARL

SCAS

Scatternet

scavenging

SCBA

SCC

SCCM

Scenario

Scenario Test

SCEP

SCEPACS

scheduled data transfer

Scheme

Scheme Owner

Schweitzer Engineering Laboratories

SCI

Science, Technology, Engineering, and Math

SCIF

SCIP

SCM

SCMS

scoping considerations

Scoping Guidance

SCOR

SCORE

SCP

Script

Scripting Language

SCRM

SCRTM

SCSI

SCTP

SCV

SCW

SDA

SDC

SDDC

SDEI

SDK

SDL

SDLC

SDMI

SDN

SDO

SDoC

SDP

SDR

SDS

SDWAN

SD-WAN

seal of approval

Search Module Lattice Isomorphism Problem

SEBoK

SEC

SECAM

SecCM

seccomp

SecDOP

Second byte of a two-byte status word

Second preimage

Second preimage resistance

Secondary market

Secret and Below Interoperability

secret key

secret key (symmetric) cryptographic algorithm

Secret key information

Secret keying material

secret seed

Sector

Sector Coordinating Council

Sector-Specific Agency

secure

secure access service edge

Secure And Fast Encryption Routine

Secure channel

secure communication protocol

secure communications

Secure Communications Interoperability Protocol

secure communications interoperability protocol (SCIP) product

Secure Computing

Secure Copy Protocol

Secure Device Authentication

Secure Digital

Secure Digital eXtended Capacity (SDXC)

Secure Digital Music Initiative

Secure DTD2000 System

Secure Element

Secure Entry Point

Secure Erase Command

Secure Exception Level

Secure File Transfer Protocol

Secure FTP

Secure Hash Algorithm

Secure Hash Algorithm 256

Secure Hash Algorithm 3

Secure Hash Algorithm Keccak

secure hash standard

Secure Initialization Authenticated Code Module

Secure Inter-Domain Routing

Secure Inter-Domain Routing Working Group

Secure Kernel

Secure LDAP

Secure Memory Encryption

Secure Messaging

Secure Messaging Key Authentication (SM-AUTH)

Secure Monitor Call

Secure Multi-Party Computation

Secure Multipurpose Internet Mail Extensions (S/MIME)

Secure Partition

Secure Partition Manager

Secure Production Identity Framework for Everyone

Secure SCADA Communications Protocol

Secure Service Container

Secure Shell

Secure Shell (network protocol)

Secure Simple Pairing

Secure Socket Tunneling Protocol

Secure Sockets Layer (SSL)

Secure Sockets Layer/Transport Layer Security

Secure Software Development Framework

secure state

Secure Telephone Unit

Secure Terminal Equipment

Secure Transport

Secure Virtual Machine

secure web gateway

Secure World

Secure/Multipurpose Internet Mail Exchange (network protocol)

Secured Component Verification

Secured Encrypted Virtualization

Secured Encrypted Virtualization with Encrypted State

Secured Encrypted Virtualization with Secured Nested Paging

securely resilient

security

Security and Privacy Profile

Security and Risk Management

security architect

security architecture

security assertion markup language (SAML)

Security Assertion Markup Language Single Sign-On

security assessment

Security Assessment and Authorization

security assessment report (SAR)

Security Association (SA)

Security Association Database (SAD)

Security Assurance Methodology

Security Assurance Specifications

security attribute

security audit

Security Audit Trail

security auditor

Security Authorization

Security Authorization & Accreditation

security authorization (to operate)

Security Authorization Boundary

security authorization package

Security Automation and Continuous Monitoring

Security Automation Domain

security banner

Security boundary

Security Capability

security categorization

security category

security concept of operations (Security CONOP)

Security Configuration Management (SecCM)

security configuration management (SecCM)

Security Configuration Wizard

Security Content Automation Program

security content automation protocol (SCAP)

Security Content Automation Protocol Validation Tool

security control

security control and privacy control

security control assessment

security control assessor (SCA)

security control baseline

Security Control Effectiveness

security control enhancements

security control inheritance

Security Control Item

Security Control Overlay Repository

security control provider

security controls

Security Credential Management System

security criteria

security design order of precedence

Security Development Lifecycle

security domain

security engineering

Security Event Management

Security Event Management Software

Security Executive Agent

Security Experts Group

security fault analysis (SFA)

Security Fault Injection Test

Security Features Users Guide

security filter

security function

security functionality

security functions

Security Gateway

Security Group Tag

security impact analysis

security incident

Security Incident and Event Management

Security Incident Event Monitoring

Security Industry Association

security information

Security Information and Event Management

Security Information and Event Management (SIEM) Tool

Security Information Management

security inspection

security kernel

security label

Security life of data

Security Management Dashboard

security marking

Security Measure

security mechanism

Security Mode Command

Security Object

security objective

Security Operations Center

Security Orchestration Automated Response

security orchestration, automation, and response

Security Parameters Index (SPI)

security perimeter

security plan

security policy

Security Policy Database (SPD)

security policy filter

Security Policy Templates

security posture

security program plan

Security properties

security protocol

Security Protocol and Data Model

security range

Security Reference Architecture

security relevance

security requirement

security requirements baseline

security requirements guide (SRG)

security requirements traceability matrix (SRTM)

security risk

Security Risk Assessment

security safeguards

security service

security solution

security specification

Security Status

security strength

security target

security technical implementation guide (STIG)

Security Technical Implementation Guideline

security test and evaluation (ST&E)

Security testing

Security Testing, Validation, and Measurement Group

Security Token Service

Security Tool Distribution

Security/System Requirements Review

Security-focused Configuration Management

Security-Oriented Code Review

security-relevant change

security-relevant information

SED

Seed

SEED

seed key

Seed Period

Seedlife

SEG

segment

Segregated Witness

SegWit

SEHOP

SEI

SEL

select (V, a, b)

selection operation

selection statement

Self testing

Self-Contained Breathing Apparatus

Self-dual Key

self-encrypting devices / self-encrypting drives (SED)

self-protection

Self-Service Module

Self-signed certificate

SEM

Semantic matching

semantic security

Semantic Web Services Architecture

Semantics

Semantics of a language

SEMI

Semi-Active Tag

semiblock

semiblock string

Semiconductor Equipment and Materials International

Semiconductor Manufacturing Cybersecurity Consortium

Semi-Free-Start

Semi-Passive Tag

Semi-Qualitative Risk Analysis

Semi-Quantitative Assessment

Sender

Sender Policy Framework

senior accountable official for risk management

senior agency information security officer (SAISO)

senior agency official for privacy

Senior Information Assurance Officer

senior information security officer (SISO)

Sensing Capability

Sensitive

Sensitive But Unclassified

sensitive compartmented information (SCI)

Sensitive Compartmented Information Facility (SCIF)

sensitive information

Sensitive Security Parameter

sensitivity

sensor

Sentences, formal

SEP

SEPA

Separation of Concerns

Separation of Duty (SOD)

SEPM

Sequence

Sequence Number

Sequence Read Archive

Serial Advanced Technology Attachment

Serial Attached SCSI

Serial Peripheral Interface

Serial Test

Server

Server Message Block

Server Name Indication

Server Platform Services Firmware

Server Routing Protocol

Server Side Includes

service

service authority

Service Class Provider

Service Component Reference Model

Service Composition

Service Description

Service Discovery Protocol

Service Interface

service level agreement (SLA)

Service Mesh

Service Model Operating System

Service Organization Control

Service Principal Name

Service Processor

Service Provider

Service-Oriented Architecture (SOA)

Serving Gateway

Session

Session Description Protocol

Session Hijack Attack

Session Initiation Protocol

set point

set theory relationship mapping

Setting the bar

Set-User-ID

SEU

SEV

SEV-ES

SEV-SNP

SFA

SFC

SFP+

SFS

SFTP

SFUG

SGCC

SGIP

SGT

S-GW

SGX

SHA

SHA-1

SHA-2

SHA-256

SHA-256(M)

SHA-256/192(M)

SHA-3

Shadow Stack

SHAKE

SHAKE256/192(M)

SHAKE256/256(M)

Shall

SHAP

Shapley Additive exPlanations

Sharding

shared control

Shared Secret

shared secret key

Shared Service Provider

Shared Service Providers

Shared Situational Awareness

shielded enclosure

Short Integer Solution

Short Message Service (SMS)

Short Message Service Chat

Short Term Key

short title

short title assignment requester (STAR)

Shortest Independent Vector Problem

Shortest Vector Problem

short-term stability

Should

Shred

Shrinkage

SHS

SIA

SIAO

SID

Side Channel Analysis with Reinforcement Learning

Sidechain

Side-Channel Attack

SIDH

SIDR

SIDR WG

SIEM

SIF

SIFA

sig

SIG

sig’

SIGE(…)

Signal Processing for Space Communications Workshop

Signal Processing System

Signaling Radio Bearer

signaling rate

Signatory

signature

Signature and Verification Operations Parallelizing Manager

Signature Block Header

signature certificate

Signature generation

Signature ID

Signature validation

Signature verification

Signature-in-question

Signed data

Signed Response

Signed Zone

significant consequences

significant cybersecurity or privacy responsibilities

SIKE

Silicon Provider

SIM

SIMD

SIMID

Similarity

Similarity digest

Similarity function

Simple Certificate Enrollment Protocol (SCEP)

Simple Key Loader

Simple Mail Transfer Protocol (SMTP)

Simple Name Server

Simple Network Time Protocol

Simple Object Access Protocol

Simple Power Analysis

Simple Public-Key GSS-API Mechanism

Simple Service Discovery Protocol

Simple Theorem Prover constraint solver

Simple t-way combination coverage

Simplified Local Internet Number Resource Management

Simulators

Single Instruction, Multiple Data

Single Log-Out

single loop controller

single point keying (SPK)

Single Sign-On

Single-Event Upset

Single-Factor

Singulation

SINIT ACM

SIP

SiPS

SIS

SISO

Site Recovery Manager

situational awareness

SIVP

Size, Weight, and Power

SK_PRF

SKCE

SKEY

Skill

Skimming

SKL

SKU

SLA

Slack Space

SLC

SLH-DSA

SLO

SLURM

Small and Medium-size Business

Small business

Small Business Administration

Small Business Innovation Research

Small Computer System Interface

Small Office/Home Office

SMAP

smart card

Smart Card Enabled Physical Access Control System

Smart contract

smart data

Smart Electric Power Alliance

Smart Grid Cybersecurity Committee

Smart Grid Interoperability Panel

Smart Meter

SMB

SMBIOS

SMBus

SMC

SMCC

SME

SMEP

SMI

SMIMEA

SMI-S

SML

smLIP

SMM

SMOS

SMPC

SMS

SMS Chat

SMT

SMTP

Snapshot

SNI

sniffer

SNMP

SNonce

SNS

SNTP

SOA

SOAP

SOAP Header

SOAP Message

SOAR

sobs

SOC

SOCHE

social engineering

Social Security Number

Society of Automotive Engineers

Society of Chemical Manufacturers and Affiliates

SOCKS Protocol

SOCMA

SoD

SOFA-B

Soft fork

software

Software and Supply Chain Assurance

Software and Systems Division

Software as a Service (SaaS)

Software Asset Management

software assurance (SwA)

Software Assurance Automation Protocol

Software Assurance Forum for Excellence in Code

Software Assurance Maturity Model

Software Assurance Reference Dataset

Software Bill of Materials

software composition analysis

software configuration management

Software Defined Network

Software Defined Perimeter

Software Defined Wide Area Network

Software Delegated Exception Interface

Software Development Kit

Software Development Life Cycle

Software Engineering Institute

Software Guard eXtensions

Software Identification

software identification (SWID) tag

Software Inventory Message and Attributes

Software Lifecycle

Software Measures and Metrics to Reduce Security Vulnerabilities

software product and executable file version

Software Restriction Policy

software supply chain

software system test and evaluation process

Software-Defined Data Center

Software-Defined Networking

Software-Defined Storage

SOHO

Solid-State Drive

SoM

SONET

SOP

SoR

SORN

SoS

Source Address

Source Address Validation

Source authentication

Source content

Source Name

Source of Randomness

Source Restriction

Source Value

Source-based Remotely Triggered Black-Holing

Sources Sought Notice

Southwestern Ohio Council for Higher Education

SOW

SOX

SPA

Space Policy Directive

space structures

spam

SPAN

SPARQL

SPD

SPDM

spear phishing

special access program

special access program facility

special category

special character

Special Cyber Operations Research and Engineering

Special Interest Group

Specialized Security-Limited Functionality

Specialized Security-Limited Functionality (SSLF) Environment

Specific

specification

Specification Limit

specification requirement

Specification versioning

SPF

SPI

SPIFFE

SPIFFE Runtime Environment

SPIFFE Verifiable Identity Document

spillage

SPIRE

SPK

SPKI

SPKM

SPL

split knowledge

split tunneling

SPM

SPN

Sponge Construction

Sponge Function

sponsor

Sponsor (of a certificate)

Sponsor (of a key)

spoofing

SPP

Sprawl

spread spectrum

SPS

SPS FW

SPSC

SPSD

SPT

spyware

SQL

SQL injection

SQL Server Management Studio

SQLi

SQN

square

SRA

SRAM

SRB

SRES

SRG

sRGB

SRK

SRM

SRP

SRR

SRTM

SRx update ID

SRxCryptoAPI

ss_K

ss_Mi

SSA

SSAA

SSC

SSCA

SSCP

SSD

SSDF

SSDP

SSE

SSE-CMM

SSFA

SSH

SSH Client

SSH Key

SSH Server

SSI

SSID

SSL

SSL Visibility

SSL/TLS

SSLF

SSLV

SSM

SSMS

SSN

SSO

SSP

SSPP

SSTP

SSVOPM

ST&E

STA

stability

stablecoin

stage

stakeholder

Staking

STAMP

Standalone Environment

standard

Standard Normal Cumulative Distribution Function

Standard operating procedures

Standard Positioning Service

Standard Red Green Blue

Standards Developing Organization

Standards Developing Organizations

Standards-Setting Organization

STAR

Start of Authority

Start-up testing

State

State Channel

State Public Safety Department

State Update

Stateful

Stateful Inspection

Stateful Protocol Analysis

Stateless

Stateless Hash-Based Digital Signature Algorithm

Stateless Inspection

Stateless Transport Tunneling

Statement coverage

Statement of Requirements

statement of work requirement

State-of-the-Art Resources

Static Analysis Reference Dataset

Static Analysis Tool Exposition

static application security tool

static code analyzer

Static Core Root of Trust for Measurement

Static key

Static key pair

Static Random Access Memory

Station

Station Access Controller

statistical bias

statistical disclosure control

statistical disclosure limitation

Statistical Ineffective Fault Attack

Statistical Test (of a Hypothesis)

Statistically Independent Events

status authority (CSA)

status word

STD

STE

Stealthwatch Flow Collector

Stealthwatch Management Center

Stealthwatch Management Console

steganography

STEM

STIG

STIX

STK

Stochastic model

Stock Keeping Unit

Stockholm International Summit on Cyber Security in SCADA and ICS

Storage

Storage Area Network

Storage Management Initiative Specification

Storage Root Key

Store a key or metadata

Stored Measurement Log

STP

STPA

stratified sampling

Stream component

Stream Control Transmission Protocol

strength of function

Strength of Function for Authenticators – Biometrics

strength of mechanism (SoM)

Strength, Weakness, Opportunity, and Threat Analysis

Strengths, Weaknesses, Opportunities, Threats

String

striped core

strong authentication

Strong Existential Unforgeability under Chosen-Message Attack

StrongAuth KeyAppliance

StrongKey Crypto Engine

StrongKey CryptoEngine

Strongly existentially UnForgeable under Chosen Message Attack

structural relationship mapping

Structured Exception Handler Overwrite Protection

Structured Product Labeling

Structured Query Language

Structured Query Language Injection

Structured Threat Information eXpression

STS

STT

STU

STVMG

subaccount

subassembly

Sub-Capability

Subcategory

Subcommittee

Subdirectory

Sub-functions

sub-hand receipt

subject

Subject (in a certificate)

Subject Alternative Name

Subject Matter Expert

subjectAltName

SubjectPublicKeyInfo

Subkey

Subkey Generation

Submitter

subordinate certificate authority

subsampling

subscriber

Subscriber Identity Module (SIM)

Subset Fault Analysis

Substation Serial Protection Protocol

Substitution–Permutation Network

subsystem

Successor

SUF-CMA

SUID

Suitability and Credentialing Executive Agent

Suite A

Suite B

Suite B compatible

summation query

Summer Undergraduate Research Fellowship

superencryption

superior certification authority

supersession

supersingular isogeny Diffie-Hellman

Supersingular Isogeny Key Encapsulation

superuser

Supervised Remote Proofing

Supervisor Mode Access Prevention

Supervisor Mode Execution Prevention

supervisory control

supervisory control and data acquisition

Supplicant Number once

supplier

Supplier’s Declaration of Conformity

supply chain

supply chain assurance

supply chain attack

supply chain element

supply chain risk

supply chain risk assessment

supply chain risk information

supply chain risk management (SCRM)

Support

Support a security strength

Support Vector Machines

Supporting Capabilities

Supporting Parties

Supporting Services

supportive relationship mapping

suppression

suppression measure

SURF

Surge Protector

survivability

susceptibility

Suspended state

suspension

SVID

SVM

SVP

SW1

SW2

SwA

SwAAP

SWAM

SWaP

SWG

SWID

SWID Tag

SWIMA

Switch

Switched Port Analyzer

SwMM-RSV

SWOT

SWSA

Sybil Attack

syllabary

Symantec Endpoint Protection

Symantec Endpoint Protection Manager

Symbol

Symmetric Card Authentication Key Authentication (SYM-CAK)

Symmetric Cryptography

Symmetric Encryption

symmetric encryption algorithm

symmetric key

sync fabric

syncable authenticators

synchronization

Synchronization Protocols

synchronous crypto-operation

Synchronous Optical Network

synchronous training

Syndrome Decoding Problem

Syntactic matching

Syntax

synthetic data generation

synthetic dataset

Synthetic Identifier

syntonization

SysAdmin, Audit, Network, Security

Syslog

system

system administrator (SA)

System and Communications Protection

System and Information Protection

System Assurance

System authority

system boundary

System Categorization

System Center Configuration Manager

system component

system context

System Contingency Plan

System Design Review

System Developer

System Development Life Cycle (SDLC)

System Development Lifecycle

System Development Platform

system element

System Flash Memory

system high

system high mode

System Identifier

system indicator

System initialization

System Integrator

system integrity

system interconnection

system life cycle

system low

System Management BIOS

System Management Bus

System Management Interrupt

System Management Mode (SMM)

System Management Tools

system of records

system of records notice

system of systems

System on Chip

system or device certificate

system owner

system owner (or program manager)

system privacy officer

System privacy requirement

System Security Authorization Agreement

System Security Engineer

system security officer

system security plan

system security requirement

system service

System Test

system user

systematic stratified sampling

systemic bias

system-related privacy risk

system-related security risk

Systems and Services Acquisition

systems engineering

Systems Engineering Body of Knowledge

Systems Management Server

systems privacy engineer

systems privacy engineering

systems security engineer

systems security engineering

Systems Security Engineering - Capability Maturity Model

systems security officer (SSO)

system-specific control

system-specific security control

Systems-Theoretic Accident Model and Processes

System-Theoretic Process Analysis

* "Relevance" merely indicates the search engine's score for a document. It is based on the search parameters and information in the document's detailed record.