Net::BitTorrent::Version - Net::BitTorrent's project-wide version numbers


Because of the problems coordinating revision numbers in a distributed version control system and across a directory full of Perl modules, this module provides a central location for the project's overall release number, the version string provided in Extended Protocol handshakes, and the Peer ID generator.


gen_node_id ( )

Returns a random 20-byte string that can be used to identify ourself in a DHT swarm.

gen_peerid ( )

Generates a unique Peer ID based on Net::BitTorrent's Specification.

Peer ID Specification

This section describes and provides examples of the Peer ID format used by this release of the Net::BitTorrent module.


This non-standard format was developed to be URL-safe, unique to the implementation, and "human parsable."

There are two distinct sections to the Peer IDs generated: the header which may be used to identify the software and its version, and the signature which is... well, it's junk. Consider this example:


Here, NB004S is the header and -rogzGB1v--git is the trailing signature.

The header consists of two uppercase characters ('NB') followed by three digits (with leading zeros) representing the distribution version and a single character used to (potentially) indicate stability: Stable or Unstable. Any deviation from this indicates a bad client. Recent stable builds will be found on CPAN.


The remainder of the Peer ID is a hyphen followed by 13 random characters in the following range:


That is, all uppercase and lowercase letters, decimal digits, as well as the hyphen, period, underscore, and tilde (66 total). These are all characters allowed in a URL without being encoded (referred to as "Unreserved Characters" in rfc 3986).

Version Numbers and Stability

Distribution version numbers will be some value less than one (1) with the revision number in the three significant decimal places.

Recent stable builds will be found on CPAN. Unstable builds will most likely be private builds or temporary uploads to CPAN where the package name matches m[\d\.\d+_\d]. See the PAUSE FAQ section entitled "Developer Releases" (



This would be the stable CPAN-ready release v0.393. The --git signature does not imply an unstable build.


Improper Peer ID; the sixth char is neither 'S' nor 'U' and < is a reserved character according to rfc: 3986.


Completely legal Peer ID generated by unstable build around v65.

See Also

RFC 3986 (URI: Generic Syntax) Section 2.3. "Unreserved Characters" (

PAUSE FAQ sub-section entitled "Developer Releases" (


This document and the specification behind it are subject to change. All modifications will be documented in the Changes file included with this distribution. All versions of this file can be found in the project's git repository.


Sanko Robinson <> -


License and Legal

Copyright (C) 2008-2009 by Sanko Robinson <>

This program is free software; you can redistribute it and/or modify it under the terms of The Artistic License 2.0. See the LICENSE file included with this distribution or For clarification, see

When separated from the distribution, all POD documentation is covered by the Creative Commons Attribution-Share Alike 3.0 License. See For clarification, see

Neither this module nor the Author is affiliated with BitTorrent, Inc.