libwandder -- C library for DER encoding and decoding.

Current Stable Version: 2.0.11

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Copyright (c) 2017-2024 The University of Waikato, Hamilton, New Zealand.
All rights reserved.

This code was originally developed by the University of Waikato WAND
research group. For further information please see http://www.wand.net.nz/.
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See the file COPYING and COPYING.LESSER for full licensing details for this
software.

Bugs, questions or comments may be sent to contact@wand.net.nz or filed as
issues on the libwandder github page: https://github.com/LibtraceTeam/libwandder

Authors:
        Shane Alcock
        Tyler Marriner


Introduction
============

Libwandder is a helper library that can be used to perform some typical
tasks related to the encoding and decoding of data structures defined
using the ASN.1 format.

This library also includes some routines that are specifically useful for
capturing and processing records using the ETSI Lawful Intercept standards.


Installation
============
After having installed the required libraries, running the following series
of commands should install libwandder

        ./bootstrap.sh (only if you've cloned the source from GitHub)
        ./configure
        make
        sudo make install

By default, libwandder installs to /usr/local - this can be changed by
appending the --prefix=<new location> option to ./configure.


API
===

There are two APIs included within libwandder: the generic API and the
ETSILI-specific API. Both APIs are extremely under-documented right now, but
hopefully this can be addressed sometime soon.

The generic API can be accessed by including the header file "libwandder.h".
This API can be used to sequentially decode each field in an encoded message,
giving the user access to the tag, class, length and values for each decoded
field. If the message only uses universal types, the API can also convert
the tags and values into printable strings.

The generic API has now been extended to support BER encoding, so that
users can take advantage of some of the liberties in BER (compared with DER)
to gain better encoding performance. Indefinite-length encoding is used for
strings, structures and sequences.

The ETSILI API can be accessed by including the header file
"libwandder_etsili.h". This API can be used to search for certain ETSI-LI
fields in the ETSI headers (e.g. timestamp, PDU length) or get a pointer to
the start of the actual captured IP payload. The ETSILI API is also capable
of decoding and interpreting many of the fields defined in the standard and
producing human-readable strings describing each field or encapsulating
structure.

Please note that the ETSI specification implemented within the libwandder API
is not yet complete -- standard IP, UMTS, Email, and IP Multimedia Communication
Contents and Intercept Related Information records are supported, but other
interception types are still on the TODO list (e.g. SMS messaging, etc).