Browse Definitions :
Definition

ASN.1 (Abstract Syntax Notation One)

Contributor(s): Joseph Flanigan

ASN.1 (Abstract Syntax Notation One) is a standard way to describe a message (a unit of application data) that can be sent or received in a network. ASN.1 is divided into two parts: (1) the rules of syntax for describing the contents of a message in terms of data type and content sequence or structure and (2) how you actually encode each data item in a message. ASN.1 is defined in two ISO standards for applications intended for the Open Systems Interconnection (OSI) framework:

  • ISO 8824/ITU X.208 specifies the syntax (for example, which data item comes first in the message and what its data type is)
  • ISO 8825/ITU X.209 specifies the basic encoding rules for ASN.1 (for example, how to state how long a data item is)

Here's an example of a message definition specified with ASN.1 notation:

Report ::= SEQUENCE { author OCTET STRING, title OCTET STRING, body OCTET STRING, biblio Bibliography }

In this very simple example, "Report" is the name of this type of message. SEQUENCE indicates that the message is a sequence of data items. The first four data items have the data type of OCTET STRING, meaning each is a string of eight-bit bytes (the term OCTET was used rather than BYTE because it can't be assumed that all computers will have eight bits in a byte). The bibliography data item is another definition named "Bibliography" that is used within this one. It might look like this:

Bibliography ::= SEQUENCE { author OCTET STRING title OCTET STRING publisher OCTET STRING year OCTET STRING }

Other data types that can be specified include: INTEGER, BOOLEAN, REAL, and BIT STRING. An ENUMERATED data type is one that takes one of several possible values. Data items can be specified as OPTIONAL (not necessarily present).

This was last updated in November 2010

Continue Reading About ASN.1 (Abstract Syntax Notation One)

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • compliance audit

    A compliance audit is a comprehensive review of an organization's adherence to regulatory guidelines.

  • regulatory compliance

    Regulatory compliance is an organization's adherence to laws, regulations, guidelines and specifications relevant to its business...

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

SearchSecurity

  • brute force attack

    Brute force (also known as brute force cracking) is a trial and error method used by application programs to decode encrypted ...

  • spyware

    Spyware is software that is installed on a computing device without the user's knowledge. Spyware can be difficult to detect; ...

  • ATM black box attack

    An ATM black box attack, also referred to as jackpotting, is a type of banking-system crime in which the perpetrators bore holes ...

SearchHealthIT

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • warm site

    A warm site is a type of facility an organization uses to recover its technology infrastructure when its primary data center goes...

  • disaster recovery (DR) test

    A disaster recovery test (DR test) is the examination of each step in a disaster recovery plan as outlined in an organization's ...

SearchStorage

  • enterprise storage

    Enterprise storage is a centralized repository for business information that provides common data management, protection and data...

  • disk array

    A disk array, also called a storage array, is a data storage system used for block-based storage, file-based storage or object ...

  • optical storage

    Optical storage is any storage type in which data is written and read with a laser. Typically, data is written to optical media, ...

Close