# vlm/asn1c

The ASN.1 Compiler

Repository: https://github.com/vlm/asn1c
Canonical: https://ross.abutalabs.com/products/asn1c
Homepage: http://lionet.info/asn1c/
Language: C
License: BSD-2-Clause
License Family: permissive
Last push: 2026-06-28T04:31:23+00:00

## Health v2 (maintenance only)
Score: 80/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 89, release rhythm 57, longevity 100
- inputs: {"age_days": 5801, "days_push": 66, "days_rel": 72, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1171, forks 620 (observed 2026-08-28T04:03:51.571572+00:00)

## What it is
asn1c is an open-source ASN.1 to C compiler that generates C/C++-compatible source code from ASN.1 module files. The generated code serializes native C structures to and from BER, OER, PER, and XER encoded data formats.

## Use cases
- compile ASN.1 specifications into C code
- encode and decode X.509 certificates in BER/DER
- implement cellular network signaling protocols
- parse ASN.1-based protocol messages in C
- generate serializers for PER-encoded data
- work with XER XML encodings of ASN.1 types

## When to choose
- you need to work with ASN.1-defined formats like X.509, LTE/3GPP signaling, or ITS communications
- you want C code generation from ASN.1 modules with BER/PER/XER support
- you need the most feature-complete open-source ASN.1 compiler

## When to avoid
- you need CER or APER encoding support, which is not implemented
- you need a complete implementation of the entire ASN.1 standard family
- you work in a language other than C/C++

## Facets
- artifact type: cli-tool
- maturity: stable
- function: compiler, serialization, parser
- domain: developer-tools, networking, security
- platform: windows, cross-platform, cli, c
- tags: asn1, ber, der, per, xer, oer, code-generator, x509, telecom, code-generation, telecommunications, linux, macos

## Member repositories
- vlm/asn1c (main) score 80

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:51.571572+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:28:33.637648+00:00, confidence not recorded.
  - readme: https://github.com/vlm/asn1c (fetched 2026-08-28T04:03:51.571572+00:00, sha 17e87150dff0)
  - homepage: http://lionet.info/asn1c/ (fetched 2026-08-29T12:34:07.152965+00:00, sha d68625a87512)
- Data as of 2026-08-30T08:39:29.467469+00:00.