D-M

Data-Link Layer

Provides reliable transit of data across a physical link using a network technology such as Ethernet. Encapsulates data into frames or cells before sending it and enables multiple computers to share a single physical medium using a media access control method like CSMA/CD.

Digital

Representation of information using numbers. The representation of information using binary digits (bits) and hexadecimal values are special cases of a digital representation.

Digital Evidence

Encompasses any and all digital data that can establish that a crime has been committed or can provide a link between a crime and its victim or a crime and its perpetrator.

E-mail, or Email

A service that enables people to send electronic messages to each other.

Equivocal Forensic Analysis

A review of the entire body of physical evidence in a given case that questions all related assumptions and conclusions. The purpose of the equivocal forensic analysis is to maximize the exploitation of physical evidence accurately to inform the reconstruction of specific crime scene behaviors.

Ethernet

A local area networking technology initially developed at the Xerox Corporation in the late 1970s. In 1980, Xerox, Digital Equipment Corporation, and Intel Corporation published the original 10 Mbps Ethernet specifications that were later developed by the Institute of Electrical and Electronic Engineers (IEEE) into the IEEE 802.3 Ethernet Standard that is widely used today. Ethernet uses CSMA/CD technology to control access to the physical medium (Ethernet cables).

Fiber Distribution Data Interface (FDDI)

A token ring network technology that uses fiber optic cables to transmit data by encoding it in pulses of light. FDDI supports a data rate of 100 Mbps and uses a backup fiber optic ring that enables hosts to communicate even if a host on the network goes down.

Hardware

The physical components of a computer.

High Risk Victim

An individual whose personal, professional, and social life continuously exposes him/her to the danger of suffering harm or loss.

Host

A computer connected to a network.

ICQ("I Seek You")

An Internet service that enables individuals to convene online in a variety of ways (text chat, voice, message boards). This service also enables file transfer and e-mail exchanges.

Internet

A global computer network linking smaller computer networks, that enable information sharing via common communication protocols. Information may be shared using electronic mail, newsgroups, the WWW, and synchronous chat. The Internet is not controlled or owned by a single country, group, organization, or individual. Many privately owned networks are not a part of the Internet.

Internet/Network Service

A useful function supported by the Internet/network such as e-mail, the Web, Usenet, or IRC. Applications give individuals access to these useful functions.

Internet Service Provider, or ISP

Any company or organization that provides individuals with access to, or data storage on, the Internet.

Internet Relay Chat (IRC)

An Internet service that enable individuals from around the world to convene and have synchronous (live) discussions. This service also enables individuals to exchange files and have private conversations. The primary networks that support this service are EFNet, Undernet, IRCnet, DALnet, SuperChat and NewNet.

Jurisdiction

The right of a court to make decisions regarding a specific person (personal jurisdiction) or a certain matter (subject matter jurisdiction).

Locard's Exchange Principle

The theory that anyone, or anything, entering a crime scene both takes something of the scene with them, and leaves something of themselves behind when they leave.

Low Risk Victim

An individual whose personal, professional, and social life does not normally expose them to a possibility of suffering harm or loss.

Media Access Control (MAC)address

A unique number that is assigned to a Network Interface Card and is used to address data at the data-link layer of a network.

Message Digest

A combination of letters and numbers generated by special algorithms that take as input a digital object of any size. A file is input into a special algorithm to produce a sequence of letters and numbers that is like a digital fingerprint for that file. A good algorithm will produce a unique number for every unique file (two copies of the same file have the same message digest).

Method of Approach

A term that refers to the offender's strategy for getting close to a victim.

Modem (see Modulator/Demodulator)

A piece of equipment that is used to connect computers together using a serial line (usually a telephone line). This piece of equipment converts digital data into an analog signal (modulation) and demodulates an analog signal into digits that a computer can process.

Modus Operandi

Modus operandi (MO) is a Latin term that means, "a method of operating." It refers to the behaviors that are committed by an offender for the purpose of successfully completing an offense. An offender's modus operandi reflects how an offender committed their crimes. It is separate from the offender's motives, or signature aspects.

Motive

The emotional, psychological, or material need that impels, and is satisfied by, a behavior.

Motivational Typology

Any classification system based on the general emotional, psychological, or material need that is satisfied by an offense or act.