ASN.1 Tools for C — Overview


The OSS® ASN.1 Tools for C is a complete development toolkit for rapidly building applications using ASN.1. This product features a powerful ASN.1:2015 capable compiler, a runtime library with ASN.1 BER, CER, DER, PER/UPER, CPER/CUPER, OER, COER, XER, CXER, E-XER, and JSON encoder/decoder engines, and a rich collection of utilities to simplify and speed your development. Our ASN.1 products support LTE Advanced Pro including NB-IoT, C-V2X and LTE-M. OSS products support the 3GPP 5G specifications.

Support for
Partial Decoding

The compiler takes ASN.1 specifications as input, and generates C language data structures plus control tables for encoding and decoding. The OSS compiler offers extensive diagnostic capabilities to minimize your development time and effort.

A set of runtime libraries provides ASN.1 encoding and decoding functions and valuable auxiliary functions to operate on application messages. The OSS runtime libraries have been ported to 500+ platforms, including many embedded platforms.

Support for JSON Encoding Rules allows serializing ASN.1 data to the popular JSON format and converting between JSON messages and ASN.1 binary messages.

Support for

Support for OER allows working with ASN.1 binary messages that can be encoded/decoded significantly faster than BER and PER messages, while being only slightly less compact than PER messages.

Support for E-XER allows generation of XML compatible with output from XML Schema tools.

If you need high speed encoding/decoding and the smallest possible memory footprint, look no further. Simply put, the OSS ASN.1 Tools for C are the most optimized ASN.1 tools you will ever find.

ASN.1 Tools for C features
  • Unparalleled speed of encoders and decoders
  • Backward compatibility guaranteed
  • ASN.1 Studio, an intuitive IDE for ASN.1 specification editing and message analysis
  • Support for partial decoding
  • Large (4096 bit) INTEGERs (for cryptographic applications)
  • Unlimited value size
  • Type representations which reflect the semantics of ASN.1 (4 byte UniversalStrings, Time classes)
  • Encoding of extensible types (unknown extensions)
  • Rich set of C representations for ASN.1 types
  • Automatic decoding for any kind of constraint
  • No implementation restrictions; never rewrite your ASN.1 to accommodate encoding limitations
  • Defer decoding of any individual field or type
  • File and socket support
  • Concatenated PDU support
  • Contents constraints (full support)
  • Generate XML stylesheet or DTD for each PDU
Free Trial

Download the ASN.1/C Tools today!

24x7 Tech Support


We are here: 24 hours a day, 7 days a week.

  • Phone: 1-888-OSS-2761 (USA and Canada)
  • Phone: 1-732-302-9669 (International)
  • Fax: 1-732-302-0023
  • Email:

Quickly receive answers to your support questions.