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Introduction to ASN.1 | Shorter introduction |
Myths about ASN.1
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- ASN.1 is robust and stable technology that has withstood the test of time, and
which continues to improve over time.
ASN.1 has been in use since 1984, but has been constantly upgraded to meet new demands.
In 1988 it was improved to support X.509 digital certificates, in 1995 it was improved
to support bandwidth and CPU-constrained devices, and in 2002 it was improved to
support XML. ASN.1 is today used in a wide range of applications and is deployed
in well over a billion computers and embedded systems devices.
Every time that you place an 800-number call ASN.1 is used. Every time you buy something
on the web ASN.1 is used. Every time you send secure email, ASN.1 is used. Almost
every time you use a multimedia product such as Microsoft NetMeeting, ASN.1 is in
use. The latest generation of aviation control systems for ground-ground and aircraft-ground
communications employ ASN.1. Companies such as Federal Express use ASN.1 in tracking
their packages. ASN.1 is used by electric and gas utilities to control the latest
generation of substations and transformers. And so on...
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- ASN.1 now supports XML in ITU-T Rec. X.693 | ISO/IEC 8825-4
(XML Encoding Rules).
- ASN.1 is an easier schema for XML than W3C XML Schema (XSD).
ASN.1 is easier to understand than XSD, for the XSD standard is intricate; among
its complexities, you need to understand namespaces to read a schema. With ASN.1
the abstract level is clearly separated from the encoding. The pure ASN.1 Schema
always results in non-ambiguous XML while when XSD is used, there are XML instances
which are ambiguous. XML is very repetitive (because of it's XML syntax), so a counter-effect
is that it can have more errors (but if a tool like
XMLSpy is used, this problem is reduced).
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- ASN.1 makes it possible to use XML where it currently is impossible due to XML's
verbose size.
By transmitting messages in PER and decoding them into XML for display or other
local XML use, ASN.1 makes it possible to use XML in bandwidth constrained applications
where currently it is impossible due to XML's verbosity. Also, due to the faster
speed of encoding/decoding messages in binary format, application components that
haven't a need to display the messages are able to run significantly faster.
- ITU-T Rec. X.694 | ISO/IEC 8825-5 (Mapping from XML
Schemas to ASN.1 moduls) now makes it possible to convert XSD to ASN.1.
- A sizeable base of tools that support ASN.1, including PER and XML, now exists.
At least a half dozen commercial tools that support X.693 are now available or are
in late beta test, and commercial and freeware implementation of X.694 are in various
stages of progress.
- The rapid degree of ASN.1:2002 features implemented by tool vendors is a testament
to the strength of the ASN.1 industry.
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