Class object
A class definition. Class definitions are objects that are instances of a generic class, or metaclass.
Classification
A determination that information requires a specific degree of protection against unauthorized disclosure together with a designation signifying that such a determination has been made.
Classification level
It is the security level of an object.
Classified information
Information that has been determined to require protection against unauthorized disclosure and is marked to indicate its classified status when in documentary form.
CleanRoom development approach
A radical departure from the traditional waterfall software development approach. The entire team of designers, programmers, testers, documenters, and customers is involved throughout the system development lifecycle. The project team reviews the programming code as it develops it, and the code is certified incrementally. There is no need for unit testing due to code certification, but the system testing and integration testing are still needed.
Clearance level
It is the security level of a subject.
Clearing
The overwriting of classified information on magnetic media such that the media may be reused. This does not lower the classification level of the media. Note: Volatile memory can be cleared by removing power to the unit for a minimum of 1 minute.
Click fraud
Deceptions and scams that inflate advertising bills with improper charge per click in an online advertisement on the Web.
Client (application)
A system entity, usually a computer process acting on behalf of a human user that makes use of a service provided by a server.
Client/server architecture
An architecture consisting of server programs that await and fulfill requests from client programs on the same or another computer.
Client/server authentication
The secure sockets layer (SSL) and transport layer security (TLS) provide client and server authentication and encryption of Web communications.
Client/server model
The client-server model states that a client (user), whether a person or a computer program, may access authorized services from a server (host) connected anywhere on the distributed computer system. The services provided include database access, data transport, data processing, printing, graphics, electronic mail, word processing, or any other service available on the system. These services may be provided by a remote mainframe using long-haul communications or within the user’s workstation in real-time or delayed (batch) transaction mode. Such an open access model is required to permit true horizontal and vertical integration.
Client-side scripts
The client-side scripts such as JavaScript, JavaApplets, and Active-X controls are used to generate dynamic Web pages.
Cloning
The practice of re-programming a phone with a mobile identification number and an electronic serial number pair from another phone.
Close-in attacks
They consist of a regular type of individual attaining close physical proximity to networks, systems, or facilities for the purpose of modifying, gathering, or denying access to information. Close physical proximity is achieved through surreptitious entry, open access, or both.
Closed-circuit television
Closed-circuit television (CCTV) can be used to record the movement of people in and out of the data center or other sensitive work areas. The film taken by the CCTV can be used as evidence in legal investigations.
Closed security environment
Refers to an environment providing sufficient assurance that applications and equipment are protected against the introduction of malicious logic during an information system life cycle. Closed security is based upon a system’s developers, operators, and maintenance personnel having sufficient clearances, authorization, and configuration control.
Cloud computing
It is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model promotes availability and is composed of five essential characteristics (i.e., on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service), three service models (i.e., cloud software as a service, cloud platform as a service, and cloud infrastructure as a service), and four deployment models (i.e., private cloud, community cloud, public cloud, and hybrid cloud).
Cluster computing
The use of failover clusters to provide high availability of computing services. Failover means the system detects hardware/software faults and immediately restarts the application on another system without requiring human intervention. It uses redundant computers or nodes and configures the nodes before starting the application on it. A minimum of two nodes is required to provide redundancy but in reality it uses more than two nodes. Variations in node configurations include active/active (good for software configuration), active/passive (good for hardware configuration), N+1 (good for software configuration), N+M (where M is more than one standby servers), and N-to-N (where clusters redistribute the services from the failed node to the active node, thus eliminating the need for a standby node). Cluster computing is often used for critical databases, file sharing on a network, high-performance systems, and electronic commerce websites. An advantage of cluster computing is that it uses a heartbeat private network connection to monitor the health and status of each node in the cluster. Disadvantages include (1) split-brain situation where all the private links can go down simultaneously, but the cluster nodes are still working, and (2) data corruption on the shared storage due to duplicate services (Wikipedia).
Coaxial cable
It is a thin cable similar to the one used in cable television connection. A coaxial cable has a solid copper wire, an inner insulation covering this core, a braided metallic ground shield, and an outer insulation.
Code division multiple access (CDMA)
A spread spectrum technology for cellular networks based on the Interim Standard-95 (IS-95) from the Telecommunications Industry Association (TIA).
Codebook attack
A type of attack where the intruder attempts to create a codebook of all possible transformations between plaintext and ciphertext under a single key.
Coder decoder (CODEC)
Coverts analog voice into digital data and back again. It may also compress and decompress the data for more efficient transmission. It is used in plain old telephone service (POTS).
Cohesion
A measure of the strength of association of the elements within a program module; the modularity is greater for higher strength modules. The best level of cohesion is functional (high-strength) and the worst level of cohesion is coincidental (low-strength). In functional cohesion, all components contribute to the one single function of a module. In coincidental cohesion, components are grouped by accident, not by plan. A higher (strong) cohesion value is better. Interfaces exhibiting strong cohesion and weak coupling are less error prone. If various modules exhibit strong internal cohesion, the inter-module coupling tends to be minimal, and vice versa.
Cold-site