install

Additional install commands

macOS

Homebrewverified · 100%

brew install libidn

provider-native install command

overview

Package summary

International domain name library

Project links

Homepage

Commands and aliases

idn

history

Project history and usage

GNU Libidn is the original GNU implementation of internationalized-domain-name handling for the IDNA2003 era, with Stringprep, Nameprep, Punycode, and related TLD validation APIs.

Project history

Libidn started as an implementation of the IETF IDN working group's Stringprep and IDNA work. The GNU manual's history section records version 0.0.0 on 2002-11-05 with Stringprep support, version 0.1.0 on 2003-01-05 with IDNA and Punycode support, and version 0.1.11 on 2003-02-26 with a command-line interface.

The March 2003 IDNA RFCs standardized the ASCII-compatible encoding approach that let applications represent non-ASCII domain labels through ASCII DNS labels beginning with the xn-- prefix. Libidn turned that standards stack into a reusable C library and command-line tool.

The manual records a GNU libc add-on proposal in March 2003 and integration in March 2004. The project page notes Fedora Core 3 included Libidn 0.5.6 in November 2004, and that version 1.0 was released on 2007-07-31 to mark stable status after production use.

Adoption history

Libidn spread through network clients and authentication-related software that needed to accept internationalized names while still speaking ASCII DNS or protocol internals. The GNU project page names GNU SASL and Shishi as users for processing user names and passwords.

After IDNA2008 replaced the IDNA2003 standards, Libidn remained important for compatibility with older software and older protocol behavior, while GNU Libidn2 became the successor implementation for IDNA2008 and TR46.

How it is used

The idn command converts domain names to and from ASCII Compatible Encoding, and the library exposes Stringprep, Punycode, IDNA, and TLD APIs for applications that need deterministic internationalized-name handling.

Why package nerds care

Libidn is a standards-history package: it ties DNS, Unicode 3.2-era string preparation, Punycode, application compatibility, and distro policy into one small dependency. Package maintainers often encounter it when deciding whether old software needs IDNA2003 compatibility or can move to libidn2.

Its glibc add-on history also makes it a useful example of how networking behavior can move between optional libraries, libc, and application-level dependencies.

Timeline

2002: Version 0.0.0 released with Stringprep implementation.
2003: Version 0.1.0 added IDNA and Punycode and became part of the GNU project.
2003: Version 0.1.11 added the command-line interface.
2004: GNU libc add-on integration recorded by the Libidn manual.
2007: Version 1.0 released to mark stable status.

Related projects

GNU Libidn2 is the successor for IDNA2008 and TR46.
RFC 3490, RFC 3491, RFC 3492, and RFC 3454 are the main IDNA2003-era standards behind the package.
GNU SASL and Shishi are named GNU consumers in the project documentation.

Sources

security posture

Risk level: green

library-like package without higher-risk signals.

Risk classifier

green risk · low confidence · appliance

Why

library-like package without higher-risk signals

Signals

metadata:library-like

Install behavior

No Homebrew bottle metadata was recorded.

Recommended review

Before unattended agent use, check whether the tool reads plaintext credentials, writes remote state, publishes artifacts, or shells out to plugins.

executables

Installed executables

Command	Kind	Exposure	Note
`idn`	executable	indexed executable	Discovered from the local executable index.

freshness

Version and freshness

These signals separate page generation age, package-manager activity, and upstream release comparison. Version lag is warned only when an evidence URL and comparable versions are present.

page generated2026-08-03

manager version1.44

manager updated

local dataunknown

upstreamnot available

latest detectednot detected

okNo freshness warnings were generated.

install metadata

Package metadata

Package key	brew:libidn
Version	1.44
Package manager	Homebrew
Homepage	https://www.gnu.org/software/libidn/
Bottle	not recorded
Service	none declared

package graph

Links come from deterministic package relationships, av.db category and tag curation, ecosystem matches, and package hub membership.

source trail

Generated from repository data

This page is generated by av-web from the private package SQLite artifact built by scripts/generate-pkg-sqlite.py.

Combined YAML source

View the package source record on GitHub.

combined/libidn.yml

Used sources

Geiger risk classifier
Nucleus package database
curated package history
pkgdb category and tag curation

Install libidn with Homebrew