Information Security Definitions

This glossary explains the meaning of key words and phrases that information technology (IT) and business professionals use when discussing IT security and related software products. You can find additional definitions by visiting WhatIs.com or using the search box below.

  • C

    Common Weakness Enumeration (CWE)

    Common Weakness Enumeration (CWE) is a universal online dictionary of weaknesses that have been found in computer software... (Continued)

  • computer exploit

    A computer exploit, or exploit, is an attack on a computer system, especially one that takes advantage of a particular vulnerability the system offers to intruders.

  • computer forensics (cyber forensics)

    Computer forensics is the application of investigation and analysis techniques to gather and preserve evidence from a particular computing device in a way that is suitable for presentation in a court of law.

  • conditional access (CA)

    Conditional access (CA) is a technology used to control access to digital television (DTV) services to authorized users by encrypting the transmitted programming.

  • content filtering (information filtering)

    On the Internet, content filtering (also known as information filtering) is the use of a program to screen and exclude from access or availability Web pages or e-mail that is deemed objectionable.

  • Content Scrambling System (CSS)

    Content Scrambling System (CSS) is a data encryption and authentication method used to protect digital versatile disk (DVD) movies from being illegally copied, distributed, and viewed from other devices, such as computer hard drives.

  • context-aware security

    Context-aware security is the use of situational information (such as identity, location, time of day or type of endpoint device) to improve information security decisions.

  • continuous authentication

    Continuous authentication is a method of verification aimed at providing identity confirmation and cybersecurity protection on an ongoing basis.

  • cookie poisoning

    On the Web, cookie poisoning is the modification of a cookie (personal information in a Web user's computer) by an attacker to gain unauthorized information about the user for purposes such as identity theft.

  • copyright

    Copyright is a legal term describing ownership of control of the rights to the use and distribution of certain works of creative expression, including books, video, movies, music and computer programs.

  • counterfeit detector pen

    A counterfeit detector pen is a felt tip pen containing an iodine solution that can be used to help identify computer-generated counterfeit bills.

  • cracker

    A cracker is someone who breaks into someone else's computer system, often on a network; bypasses passwords or licenses in computer programs; or in other ways intentionally breaches computer security.

  • CRAM (challenge-response authentication mechanism)

    CRAM (challenge-response authentication mechanism) is the two-level scheme for authenticating network users that is used as part of the Web's Hypertext Transfer Protocol (HTTP).

  • Crash Course: Spyware

    In general, spyware is any technology that aids in gathering information about a person or organization without their knowledge.

  • crimeware

    Crimeware is programming that is designed to facilitate illegal online activity. The use of crimeware is primarily financially motivated.

  • cross-site scripting (XSS)

    Cross-site scripting (XSS) is a type of injection security attack in which an attacker injects data, such as a malicious script, into content from otherwise trusted websites.

  • cryptanalysis

    Cryptanalysis is the study of ciphertext, ciphers and cryptosystems with the aim of understanding how they work and finding and improving techniques for defeating or weakening them.

  • crypto

    Depending on its usage, crypto can be a short form for cryptography or for encryption.

  • cryptographic checksum

    A cryptographic checksum is a mathematical value (called a checksum) that is assigned to a file and used to "test" the file at a later date to verify that the data contained in the file has not been maliciously changed.

  • cryptography

    Cryptography is a method of protecting information and communications through the use of codes so that only those for whom the information is intended can read and process it.

  • cryptology

    Cryptology is the mathematics, such as number theory, and the application of formulas and algorithms, that underpin cryptography and cryptanalysis.

  • cryptoperiod (key lifetime or a validity period)

    A cryptoperiod (sometimes called a key lifetime or a validity period) is a specific time span during which a cryptographic key setting remains in effect.

  • cryptosystem

    A cryptosystem is a structure or scheme consisting of a set of algorithms that converts plaintext to ciphertext to encode or decode messages securely.

  • CSR (Certificate Signing Request)

    A Certificate Signing Request or CSR is a specially formatted encrypted message sent from a Secure Sockets Layer (SSL) digital certificate applicant to a certificate authority (CA) validating the information required by the CA in order for it to issue a certificate.

  • CSSLP (certified secure software lifecycle professional)

    The CSSLP (certified secure software lifecycle professional) is a certification for security professionals who wish to strengthen and demonstrate their knowledge about application security.

  • cut-and-paste attack

    A cut-and-paste attack is an assault on the integrity of a security system in which the attacker substitutes a section of ciphertext (encrypted text) with a different section that looks like (but is not the same as) the one removed.

  • CVSS (Common Vulnerability Scoring System)

    The CVSS (Common Vulnerability Scoring System) rates the severity of software vulnerabilities so organizations are able to prioritize mitigation.

  • cyber attribution

    Cyber attribution is the process of tracking, identifying and laying blame on the perpetrator of a cyberattack or other hacking exploit.

  • Cyber Storm

    Cyber Storm is the name of a simulated attack exercise conducted by the U.S. Department of Homeland Security (DHS) February 6-10, 2006 to evaluate whether or not the country could withstand a real attack of similar magnitude...

  • cybercrime

    Cybercrime is any criminal activity that involves a computer, networked device or a network.

  • cyberextortion

    Cyberextortion is a crime involving an attack or threat of an attack coupled with a demand for money or some other response in return for stopping or remediating the attack.

  • cybersecurity insurance (cybersecurity liability insurance)

    Cybersecurity insurance, also called cyber liability insurance or cyber insurance, is a contract that an entity can purchase to help reduce the financial risks associated with doing business online.

  • cyberstalking

    Cyberstalking is a crime in which the attacker harasses a victim using electronic communication, such as e-mail or instant messaging (IM), or messages posted to a Web site or a discussion group.

  • cyberterrorism

    According to the U.S. Federal Bureau of Investigation, cyberterrorism is any 'premeditated, politically motivated attack against information, computer systems, computer programs, and data which results in violence against non-combatant targets by sub-national groups or clandestine agents.'

  • cyberwarfare

    Cyberwarfare is computer- or network-based conflict involving politically motivated attacks by a nation-state on another nation-state.

  • cypherpunk

    Cypherpunk, a term that appeared in Eric Hughes' "A Cypherpunk's Manifesto" in 1993, combines the ideas of cyberpunk, the spirit of individualism in cyberspace, with the use of strong encryption (ciphertext is encrypted text) to preserve privacy.

  • What is cybersecurity? Everything you need to know

    Cybersecurity is the protection of internet-connected systems -- including hardware, software and data -- from cyberattacks.

  • D

    data breach

    A data breach is a confirmed incident in which sensitive, confidential or otherwise protected data has been accessed and/or disclosed in an unauthorized fashion.

  • Data Encryption Standard (DES)

    The Data Encryption Standard (DES) is an outdated symmetric-key method of data encryption.

  • data encryption/decryption IC

    A data encryption/decryption IC is a specialized integrated circuit (IC) that can encrypt outgoing data and decrypt incoming data...

  • data key

    In cryptography, a data key is a key (a variable value that is applied to a string or block of text to encrypt or decrypt it) that is used to encrypt or decrypt data only and is not used to encrypt or decrypt other keys, as some encryption formulas call for.

  • data masking

    Data masking is a method of creating a structurally similar but inauthentic version of an organization's data that can be used for purposes such as software testing and user training. The purpose is to protect the actual data while having a functional substitute for occasions when the real data is not required.

  • data splitting

    Data splitting is an approach to protecting sensitive data from unauthorized access by encrypting the data and storing different portions of a file on different servers.

  • decipher

    All three terms - decipher, decrypt, and decode - mean to convert ciphertext into the original, unencrypted plaintext.

  • defense in depth

    Defense in depth is the coordinated use of multiple security countermeasures to protect the integrity of the information assets in an enterprise... (Continued)

  • Defense Message System (DMS)

    The Defense Message System (DMS) is a secure X.400-based e-mail system developed by the United States government in conjunction with industry partners to ensure safety for critical operations.

  • deniable encryption

    Deniable encryption is a type of cryptography that allows an encrypted text to be decrypted in two or more ways, depending on which decryption key is used.

  • denial-of-service attack

    A denial-of-service attack is a security event that occurs when an attacker prevents legitimate users from accessing specific computer systems, devices, services or other IT resources.

  • deperimeterization

    In network security, deperimeterization is a strategy for protecting a company's data on multiple levels by using encryption and dynamic data-level authentication.

  • deprovisioning

    Deprovisioning is the process of removing access to a system from an end user who will no longer be utilizing that system.

  • destruction of service (DeOS) attack

    A destruction-of-service (DeOS) attack is a form of cyberattack that targets an organization's entire online presence as well as their ability to recover from the attack afterwards.

  • dictionary attack

    A dictionary attack is a method of breaking into a password-protected computer or server by systematically entering every word in a dictionary as a password. A dictionary attack can also be used in an attempt to find the key necessary to decrypt an encrypted message or document.

  • differential power analysis (DPA)

    A differential power analysis (DPA) attack is an exploit based on analysing the correlation between the electricity usage of a chip in a smart card and the encryption key it contains.

  • Diffie-Hellman key exchange (exponential key exchange)

    Diffie-Hellman key exchange, also called exponential key exchange, is a method of digital encryption that uses a number raised to specific powers to produce decryption keys that are never directly transmitted, making the task of a would-be code breaker mathematically overwhelming... (Continued)

  • digest authentication

    Digest authentication is a method of authentication in which a request from a potential user is received by a network server and then sent to a domain controller... (Continued)

  • digital certificate

    A digital certificate, also known as a public key certificate, is used to cryptographically link ownership of a public key with the entity that owns it.

  • digital signature

    A digital signature is a mathematical technique used to validate the authenticity and integrity of a message, software or digital document.

  • Digital Signature Standard (DSS)

    Digital Signature Standard (DSS) is the digital signature algorithm(DSA) developed by the U.S. National Security Agency (NSA) to generate a digital signature for the authenticationof electronic documents.

  • directory harvest attack (DHA)

    A directory harvest attack (DHA) is an attempt to determine the valid e-mail addresses associated with an e-mail server so that they can be added to a spam database.

  • directory traversal

    Directory traversal is a form of HTTP exploit in which a hacker uses the software on a Web server to access data in a directory other than the server's root directory... (Continued)

  • distributed denial of service (DDoS) attack

    A distributed denial-of-service (DDoS) attack is an attack in which multiple compromised computer systems attack a target, such as a server, website or other network resource, and cause a denial of service for users of the targeted resource.

  • DMZ (networking)

    In computer networks, a DMZ (demilitarized zone), also sometimes known as a perimeter network or a screened subnetwork, is a physical or logical subnet that separates an internal local area network (LAN) from other untrusted networks -- usually the public internet.

  • DNS attack

    A DNS attack is an exploit in which an attacker takes advantage of vulnerabilities in the domain name system (DNS).

  • DNS over HTTPS (DoH)

    DNS over HTTPS (DoH) is a relatively new protocol that encrypts domain name system traffic by passing DNS queries through a Hypertext Transfer Protocol Secure encrypted session.

  • DNS rebinding attack

    DNS rebinding is an exploit in which the attacker uses JavaScript in a malicious Web page to gain control of the victim's router. The attack works on widely-used routers such as D-Link and Linksys and could, in fact, target any device that uses a default password and Web-based administration... (Continued)

  • domain fluxing

    Domain fluxing is a technique used by botnet operators for their command-and-control infrastructures to avoid detection by security technologies and researchers attempting to shut their botnets down.

  • domain generation algorithm (DGA)

    A domain generation algorithm or DGA is a computer program used to create domain names, typically for the purpose of propagating remotely controlled Web-based malware.

  • domain rotation

    Domain rotation is a technique use by malware distributors to drive traffic from multiple domains to a single IP address that is controlled by the distributor. The goal of domain rotation is to make it harder for a network administrator to blacklist the malware distributor.

  • DomainKeys

    DomainKeys is an anti-spam software application in development at Yahoo that uses a form of public key cryptography to authenticate the sender's domain.

  • DOS (Disk Operating System)

    DOS (Disk Operating System) can refer to a computer operating system that is loaded from a disk drive or to an operating system based on Microsoft Disk Operating System (MS-DOS).

  • drive-by pharming

    Drive-by pharming is a vulnerability exploitation method in which the attacker takes advantage of an inadequately unprotected broadband router to gain access to user data... (Continued)

  • DSO exploit (data source object exploit)

    A data source object (DSO) exploit is a form of spyware that takes advantage of data binding to gain access to the hard drive of a computer connected to the Internet.

  • dumpster diving

    Dumpster diving is looking for treasure in someone else's trash.

  • Duo Security

    Duo Security is a vendor of cloud-based two-factor authentication products.

  • Duqu (W32.Duqu)

    Duqu is a remote access Trojan (RAT) that is designed to steal data from computers it infects.

  • E

    Echelon

    Echelon is an officially unacknowledged U.S.-led global spy network that operates an automated system for the interception and relay of electronic communications.

  • EINSTEIN

    EINSTEIN monitors and analyzes Internet traffic when it moves in and out of U.S. federal computer networks.

  • electro-optical fingerprint recognition

    Electro-optical fingerprint recognition is a biometric technology that provides for the scanning, comparison, and identification of fingerprints without the traditional need for ink and paper.

  • Electronic Code Book (ECB)

    Electronic Code Book (ECB) is a mode of operation for a block cipher, with the characteristic that each possible block of plaintext has a defined corresponding ciphertext value and vice versa.

  • electronic discovery (e-discovery or ediscovery)

    Electronic discovery (also called e-discovery or ediscovery) refers to any process in which electronic data is sought, located, secured, and searched with the intent of using it as evidence in a civil or criminal legal case.

  • Electronic Signatures in Global and National Commerce Act (e-signature bill)

    The Electronic Signatures in Global and National Commerce Act (often referred to as the e-signature bill) specifies that in the United States, the use of a digital signature is as legally valid as a traditional signature written in ink on paper.

  • Elk Cloner

    Elk Cloner was the first computer virus known to have spread in the wild.

  • elliptical curve cryptography (ECC)

    Elliptical curve cryptography (ECC) is a public key encryption technique based on elliptic curve theory that can be used to create faster, smaller, and more efficient cryptographic keys.

  • email spam

    Email spam, or junk email, is unsolicited bulk messages sent through email with commercial, fraudulent or malicious intent.

  • email spoofing

    Email spoofing is the forgery of an email header so that the message appears to have originated from someone or somewhere other than the actual source.

  • email virus

    An email virus consists of malicious code that is distributed in email messages, and it can be activated when a user clicks on a link in an email message, opens an email attachment or interacts in some other way with the infected email message.

  • Encrypting File System (EFS)

    The Encrypting File System (EFS) is a feature of the Windows 2000 operating system that lets any file or folder be stored in encrypted form and decrypted only by an individual user and an authorized recovery agent.

  • encryption

    Encryption is the method by which information is converted into secret code that hides the information's true meaning.

  • end-to-end encryption (E2EE)

    End-to-end encryption is a secure method of transferring data from one end device to another without allowing third-party interference.

  • endpoint detection and response (EDR)

    Endpoint detection and response (EDR) is a category of tools and technology used for protecting computer hardware devices–called endpoints—from potential threats.

  • endpoint fingerprinting

    Endpoint fingerprinting is a feature of enterprise network access control (NAC) products that enables discovery, classification and monitoring of connected devices, including non-traditional network endpoints such as smartcard readers, HVAC systems, medical equipment and IP-enabled door locks. Such endpoints are sometimes referred to as "dumb devices."

  • endpoint security management

    Endpoint security management is a policy-based approach to network security that requires endpoint devices to comply with specific criteria before they are granted access to network resources.

  • Escrowed Encryption Standard (EES)

    The Escrowed Encryption Standard (EES) is a standard for encrypted communications that was approved by the U.S. Department of Commerce in 1994 and is better known by the name of an implementation called the Clipper chip.

  • ethical hacker

    An ethical hacker, also referred to as a white hat hacker, is an information security expert who systematically attempts to penetrate a computer system, network, application or other computing resource on behalf of its owners -- and with their permission -- to find security vulnerabilities that a malicious hacker could potentially exploit.

  • ethical worm

    An ethical worm is a program that automates network-based distribution of security patches for known vulnerabilities.

  • Evil Corp

    Evil Corp is an international cybercrime network that uses malicious software to steal money from its victims' bank accounts.

  • evil maid attack

    An evil maid attack is a security exploit that targets a computing device that has been shut down and left unattended.  An evil maid attack is characterized by the attacker's ability to physically access the target multiple times without the owner's knowledge. 

  • evil twin

    An evil twin, in security, is a rogue wireless access point that masquerades as a legitimate hot spot.

  • executable

    In computers, to execute a program is to run the program in the computer, and, by implication, to start it to run.

  • Extensible Authentication Protocol (EAP)

    The Extensible Authentication Protocol (EAP) is a protocol for wireless networks that expands on authentication methods used by the Point-to-Point Protocol (PPP), a protocol often used when connecting a computer to the Internet.

SearchCloudSecurity

SearchNetworking

SearchCIO

SearchEnterpriseDesktop

SearchCloudComputing

ComputerWeekly.com

Close