Glossary

This book includes a glossary so that you can find terms and acronyms easily. It has several important features you need to know. First, every major acronym in the book appears here—even if there’s a better than even chance you already know what the acronym stands for. (I mentioned some acronyms in passing or as part of amplifying information that don’t appear here.) This way, there isn’t any doubt that you’ll always find everything you need to use the book properly.

Second, these definitions are specific to the book. In other words, when you look through this glossary, you’re seeing the words defined in the context in which they’re used in this book. This might or might not always coincide with current industry usage since the computer industry changes the meaning of words so often.

Finally, I’ve used a conversational tone for the definitions here in most cases. This means that the definitions might sacrifice a bit of puritanical accuracy for the sake of better understanding. The purpose of this glossary is to define the terms in such a way that there’s less room for misunderstanding the intent of the book as a whole.

Abstract Syntax Notation One (ASN.1): A specialized language that determines the method of transferring data between dissimilar systems. The language defines a common syntax that ensures the data the recipient receives is the same as the data the sender sent. ASN.1 is an ISO/ITU (International Organization for Standardization/International Telecommunication Union) standard that originally appeared as an addition to the Open System Interconnection (OSI) model. The language first appeared in 1984 as part of the Consultative Committee for International Telegraphy and Telephony (CCITT) X.409 standard and eventually became the separate X.208 standard in 1998.
Active Directory Services Interface (ADSI): A set of APIs used to access Active Directory, the central repository of information in Windows. Active Directory is a hierarchical database used to store many types of information in a somewhat free-form format. ADSI allows access to both Active Directory data and the schema, which means you can use it to create new database elements, as well as remove elements that are no longer in use.
ADSI: See Active Directory Services Interface
Advanced Encryption Standard (AES): The mathematical basis for performing symmetric encryption and decryption of data. The algorithm originally appeared as the Rijndael algorithm, after it’s inventors (Joan Daemen and Vincent Rijmen). This is a block cipher that can accept a number of data block sizes and key lengths. Many companies now use this algorithm as a replacement for the DES and Triple DES algorithms.
AES: See Advanced Encryption Standard
API: See Application Programming Interface
Application Programming Interface (API): A method of defining a standard set of function calls and other interface elements. It usually defines the interface between a high-level language and the lower-level elements used by a device driver or operating system. The ultimate goal is to provide some type of service to an application that requires access to the operating system or device feature set.
ASN.1: See Abstract Syntax Notation One
Attribute: An attribute expresses a feature peculiar to an object. When referring to a database, each field has attributes that express what type of information the field contains, the length of the field, the field name, and the number of decimals. When referring to a display, the attribute expresses pixel color, intensity, and position. In programming, an attribute can also specify some type of object functionality, such as the method used to implement security.
Authentication: The act of validating the identity of a caller. This task can include any of a number of validation techniques, such as the use of passwords.
Authorization: The act of providing access to specific services or resources based on the authenticated identity of a caller or other entity. Authorization gives the requesting party permission to use the specific service or resource.

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