Work factor
The amount of work necessary for an attacker to break the system or network should exceed the value that the attacker would gain from a successful compromise.
Workflow Management System (WFMS)
A computerized information system that is responsible for scheduling and synchronizing the various tasks within the workflow, in accordance with specified task dependencies, and for sending each task to the respective processing entity (e.g., Web server or database server). The data resources that a task uses are called work items. WFMS is the basis for work flow policy access control system.
Workflow manager
The sub-component that enables one component to access services on other components to complete its own processing in a service-oriented architecture (SOA). The workflow manager determines which external component services must be executed and manages the order of service execution.
Workstation
(1) A piece of computer hardware operated by a user to perform an application. Provides users with access to the distributed information system or other dedicated systems; input/output via a keyboard and video display terminal; or any method that supplies the user with the required input/output capability. Computer power embodied within the workstation may be used to furnish data processing capability at the user level. (2) A high-powered PC with multifunctions and connected to the host computer.
World Wide Web (WWW)
A system of Internet hosts that support documents formatted in HTML, which contains links to other documents (hyperlinks), and to audio and graphics images. Users can access the Web with special applications called browsers (e.g., Netscape and Internet Explorer).
Worm
A self-replicating and self-contained program that propagates (spreads) itself through a network into other computer systems without requiring a host program or any user intervention to replicate.
Write
A fundamental operation that results only in the flow of information from a subject to an object.
Write access
Permission to write an object.
Write blocker
A device that allows investigators to examine media while preventing data writes from occurring on the subject media.
Write protection
Hardware or software methods of preventing data from being written to a disk or other medium.
X
X3.93
Used for data encryption algorithm (All standards starting with X belong to International Organization for Standards ISO).
X9.9
Used for message authentication.
X9.17
Used for cryptographic key management (Financial Institution Key Management).
X9.30
Used for digital signature algorithm (DSA) and the secure hash algorithm (SHA-1).
X9.31
Used for rDSA signature algorithm.
X9.42
Used for agreement of symmetric keys using discrete logarithm cryptography.
X9.44
Used for the transport of symmetric algorithm keys using reversible public key cryptography.
X9.52
Used for triple data encryption algorithm (TDEA).
X9.62
Used for elliptic curve digital signature algorithm.
X9.63
Used for key agreement and key transport using elliptic curve-based cryptography.
X9.66
Used for cryptography device security.
X12
Defines EDI standards for many U.S. industries (e.g., healthcare and insurance).
X.21
Defines the interface between terminal equipment and public data networks.
X.25
A standard for the network and data link levels of a communications network. It is a WAN protocol.
X.75
A standard that defines ways of connecting two X.25 networks.
X.121
Network user address used in X.25 communications.
X.400
Used in e-mail as a message handling protocol for reformatting and sending e-mails.
X.500
A standard protocol used in electronic directory services.
X.509
A standard protocol used in digital certificates and defines the format of a public key certificate.
X.800
Used as a network security standard.
X. 509 certificate
Two types of X.509 certificates exist: The X.509 public key certificate (most commonly used) and The X.509 attribute certificate (less commonly used). The X.509 public key certificate is created with the public key for a user (or device) and a name for the user (or device), together with optional information, is rendered unforgeable by the digital signature of the certification authority (CA) that issued the certificate, and is encoded and formatted according to the X.509 standard. The X.509 public key certificate contains three nested elements: (1) the tamper-evident envelope, which is digitally signed by the source, (2) the basic certificate content (e.g., identifying information about a user or device and public key), and (3) extensions that contain optional certificate information.
XACML
Extensible access control markup language (XACML) combined with extensible markup language (XML) access control policy is a framework that provides a general-purpose language for specifying distributed access control policies.
XDSL
Digital subscriber line is a group of broadband technology connecting home/business telephone lines to an Internet service provider’s (ISP’s) central office. Several variations of XDSL exist such as SDSL, ADSL, IDSL, and HDSL.
XHTML
Extended hypertext markup language (XHTML) is a unifying standard that brings the benefits of XML to those of HTML. XHTML is the new Web standard and should be used for all new Web pages to achieve maximum portability across platforms and browsers.
XML
Extensible markup language, which is a meta-language, is a flexible text format designed to describe data for electronic publishing. The Web browser interprets the XML, and the XML is taking over the HTML for creating dynamic Web documents.
XML encryption
A process/mechanism for encrypting and decrypting XML documents or parts of documents.
XML gateways
XML gateways provide sophisticated authentication and authorization services, potentially improving the security of the Web service by having all simple object access protocol (SOAP) messages pass through a hardened gateway before reaching any of the custom-developed code. XML gateways can restrict access based on source, destination, or WS-Security authentication tokens.
XML schema
A language for describing and defining the structure, content, and semantics of XML documents.
XML signature
A mechanism for ensuring the origin and integrity of XML documents. XML signatures provide integrity, message authentication, or signer authentication services for data of any type, whether located within the XML that includes the signature or elsewhere.
XOR
Exclusive OR, which is a Boolean operation, dealing with true or false condition (that is, something is either true or false but not both). It is the bitwise addition, modulo2, of two bit strings of equal length. For example, XOR is central to how parity data in RAID levels is created and used within a disk array (that is, yes parity or no parity). It is used for the protection of data and for the recovery of missing data.