counterterrorism and computers

Counterterrorism is the effort to detect, identify, and neu- tralize terrorist groups and prevent attacks. Not surpris- ingly, information technology plays a part in every phase of this effort—and sometimes even becomes part of the battlefield.

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The Web and other Internet services are an important part of the battle against terrorism, not least because terrorists themselves are beginning to use online tools effectively (see cybeRteRRoRism). The Internet inherently allows for considerable anonymity (see anonymityandthe inteR-

net). However, any online activity leaves traces, however virtual, and surveillance, intelligence, and forensic tech- niques are being adapted to this new medium (see com-

puteRfoRensics).

By putting so much material online, terrorists are expos- ing themselves to the increasingly sophisticated data min- ing and “semantic Web” tools that are being developed. These tools can, for example, identify material likely to be of interest (and summarize it) and even analyze the rela- tionship between individuals or groups based on their writ- ing or verbal communications. Of course such results must still be reviewed and acted upon by trained human analysts. Further, surveillance tools that are deployed too widely or indiscriminately are liable to raise privacy concerns.         CORBA

In recent years the U.S. Department of Homeland Secu- rity has apparently been developing more sophisticated data-mining and pattern-recognition programs (see bio-

metRics and datamining). One is called ADVISE, or Anal- ysis, Dissemination, Visualization, Insight, and Semantic Enhancement. This at least suggests an attempt not to sim- ply find matches between e-mail, online postings, or other textual data, but to construct profiles of a person’s activity and/or intentions, which could presumably then be com- pared with terrorist or criminal profiles.

Surveillance or wiretapping of specific individuals also raises legal issues, particularly with recent revelations of so-called warrantless wiretaps. Officials have claimed that there are relatively few such cases (perhaps fewer than 100 per year), but the Bush administration’s claim that it did not need to follow Foreign Intelligence Surveillance Act (FISA) procedures raised considerable controversy, and a court decision forced the administration to seek affirmation of its powers by Congress.

Intelligence officials argue that existing FISA proce- dures are too cumbersome to deal with the Internet. Old- style wiretapping involved specific telephone instruments and lines, but on the Internet the routing of information is constantly changing, and a person may use several different devices and types of communication. Thus it is argued that the warrant must be broad enough to apply to the person, not a particular means of communication. It is also argued that the global nature of the network also means that dis- tinctions about whether persons are inside or outside of the United States may no longer be as relevant.

Privacy and civil liberties advocates tend to agree that some updating of warrant procedures to deal with modern technology is necessary, but they point to secretiveness and lack of effective legal oversight resulting in a lack of accountability for government surveillance programs. This concern has also been fueled by a succession of rev- elations that surveillance programs are more extensive than previously thought. (This includes the involvement of telecommunications and Internet service providers and the use of FBI “national security letters”—essentially secret subpoenas.)

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Besides the gathering and analysis of intelligence, computer applications are used in the intelligence and counterter- rorism community for many of the same functions found in any large enterprise. These applications include e-mail, personal information management, collaborative creation or review of documents, scheduling and project manage- ment, and so on.

Intelligence agencies are even adopting some popular emerging Web technologies. First came Intellipedia, a clas- sified version of Wikipedia serving as a knowledge base for intelligence professionals (see Wikis and Wikipedia). In late 2007 the director of national intelligence (DNI) launched A-Space, which includes Intellipedia, while add- ing other extensive databases, online office facilities (simi- lar to google Apps), and even blogs and a mySpace-like component (see socialnetWoRking).

Further Reading

Derosa, mary. Data Mining and Data Analysis for Counterterrorism.

Washington, D.C.: Center for Strategic & International Stud- ies, 2004.

Hoover, J. Nicholas. “U.S. Spy Agencies go Web 2.0 in Effort to Better Share Information.” InformationWeek, August 23, 2007. Available online. URL: http://www.informationweek. com/story/showArticle.jhtml?articleID=201801990. Accessed September 10, 2007.

Lichtblau, Eric. “F.B.I. Data mining Reached beyond Initial Tar- gets.” New York Times, September 9, 2007. Available online. URL: http://www.nytimes.com/2007/09/09/washington/09fbi. html. Accessed September 10, 2007.

miller, greg. “Spy Chief Reveals Details of Operations.” Los Ange- les Times. Available online. URL: http://www.latimes.com/ news/nationworld/nation/la-na-intel23aug23,0,6229712. story?coll=la-home-center. Accessed September 10, 2007. mohammed, Arshad, and Sara Kehaulani goo. “government

Increasingly Turning to Data mining.” Washington Post,

June 15, 2006, p. D03. Available online. URL: http://www. whisperingwires.info/. Accessed September 10, 2007. National Research Council. Information Technology for Counterter-

rorism: Immediate Actions and Future Possibilities. Washing- ton, D.C.: National Academies Press, 2003.

Taipale, K. A. “Whispering Wires and Warrantless Wiretaps: Data mining and Foreign Intelligence Surveillance.” Bulletin on Law & Security, spring 2006. Available online. URL: http:// www.whisperingwires.info/. Accessed September 10, 2007.

CPU

The CPU, or central processing unit, is the heart of a com- puter, the place where data is brought in from input devices, processed, and sent to output devices. (This article describes the CPU from the point of view of desktop micromputers, where it is a single large silicon chip and supporting chips; see mainfRame for a discussion of that earlier architecture,

micRopRocessoR for desktop and portable CPUs, and chip

and chipset for physical design of components.)

The CPU consists of two major parts. The arithmetic- logic unit performs arithmetic or logical operations on pairs of numbers brought in from memory and stored in special locations called registers (see aRithmeticlogicunit). For example, the CPU can add a value from main memory to a value stored in a register and store the result back into memory. In addition to addition, subtraction, multiplica- tion, and division, the CPU can logically compare the indi- vidual bits in two values, performing such operations as AND, where the result is 1 only if both bits are ones, or OR, where the result is 1 if either bit is one. The power of a CPU is measured either in the number of clock cycles that drive it each second (see clockspeed) or the number of standard instructions it can execute in a second. For modern PCs, clock speeds range into the billions of cycles per second (gigahertz) and millions of instructions per second (most instructions take more than one cycle to be completed).

The other key part of the CPU is the control unit, which determines when (and which) instructions will be executed. Operations to be performed are specified by instruction val- ues that are the lowest level representation of program code, sometimes called machine code. An index register is used to keep track of the current instruction. As instructions are processed, control signals can indicate special conditions, CPU       

such as a result being negative. Based on the instructions and signals, the CPU can skip over some instructions, jump- ing to another location in the program.

The main memory or RAm (random access memory) contains both the program instructions and the data being used by the program, which in turn can be read from a disk or other medium or written back to storage. The effec- tive speed of the system is derived not only from the clock speed but from the speed at which data travels over the sys- tem bus, a set of wires that each carry one data bit, as well as the operating speed of the memory chips themselves (see

clockspeed and bus).

The access of programs to the CPU is controlled in turn by the operating system. modern operating systems share the CPU with several running programs, doling out execu- tion time according to a scheduling algorithm that takes into account the possible special priority of some programs (see multitasking).

Further Reading

Brain, marshall. “How microprocessors Work.” Available online. URL: http://computer.howstuffworks.com/microprocessor.htm. Accessed June 30, 2007.

mano, m. morris, and Charles Kime. Logic and Computer Design Fundamentals. 4th ed. Upper Saddle River, N.J.: Prentice Hall, 2007.

Stokes, Jon. Inside the Machine: An Illustrated Introduction to Micro- processors and Computer Architecture. San Francisco: No Starch Press, 2006.