In many cases, information security may be a vital component of a general wideband data radio system. Several security services are permitted for implementation in these systems. The services are standards options and they operate within the bounds of the interfaces defined for non-secure operation. This security overlay may be used to provide end-to-end security of information transferred across a general wideband data radio system or the security overlay may be used to just protect information across the air interface. The purpose of this document is to define the meaning of these security services. The definition and detail of how security services are provided is outside the scope of this document. A general wideband data radio communications system consists of subscriber units, base stations and other fixed equipment for single-site to wide area operation and computer end host system equipment. The subscriber units include portable radios for handheld operation and mobile radios for vehicular operation. The base stations are for geographically fixed installations. A standard should exist to describe any given specific instance of such a general wideband data radio system. This document will refer to such a specific instance of a general wideband data radio system as defined by the TIA-902 series of standards. This document provides an overview of the security services available in wideband data radio systems. It provides the context in which to understand when certain security services may be desired and gives a general high-level description of how they are provided. The purpose of security services is to neutralize information security threats to a system. The nature of these threats is discussed in this document, and the security services to counter these threats are defined. In general, the subject of security includes encryption, and this topic is discussed in general terms to explain the different levels of encryption algorithms available within the standard, and their application to security services. In the context of this document, the specific security requirements are generalized into three security topics: -- Confidentiality (also known as Privacy) -- Authentication and Integrity -- Key management These three categories correspond to the security services available to wideband data radio systems. This document does not provide specific message formats or operational details of these security services