scope:

This International Standard specifies a notation for abstract syntax definition called Abstract Syntax Notation One (ASN.1).

This International Standard defines a number of simple types, with their tags, and specifies a notation for referencing these types and for specifying values of these types.

This International Standard defines mechanisms for constructing new types from more basic types, and specifies a notation for defining such structured types and assigning them tags, and for specifying values of these types.

This International Standard defines character sets (by reference to other International Standards) for use within ASN.1.

This International Standard defines a number of useful types (using ASN.l), which can be referenced by users of ASN.1.

The ASN.l notation can be applied whenever it is necessary to define the abstract syntax of information. It is particularly, but not exclusively, applicable to application protocols.

The ASN.1 notation is also referenced by other presentation layer standards which define encoding rules for the simple types, the structuredtypes, the character string types and the useful types defined in ASN.1.