Short introduction

​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...

​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).