Crypt::IDA is a Perl module that implements Rabin's Information Dispersal Algorithm. This is what's known as a "threshold system": a secret is divided into n shares with the property that any k (the "quorum" or "threshold") of those shares (with k <= n) can be combined at a later time to reconstruct the secret. The algorithm should be cryptographically secure in the sense that if fewer shares than the quorum k are presented, no information about the secret is revealed. The module uses Math::FastGF2 to efficiently implement the algorithm, making it suitable for securely sharing and distributing even large files. The Crypt::IDA::ShareFile module implements a file format for creating, storing, and distributing shares created with Crypt::IDA.
vrbroadcast is a video on demand and media distribution server. It supports hierarchical networks of servers that will automaticaly update information on the available media. It has a GUI that is only available in German, but the server was written with multi-language support in mind.
Com' On Feel The Noize is a tool generating an M3U list from any Ogg/MP3 available on a specific network. Each computer on the network runs, via cron, a backend script that feeds a common database. Frontend scripts can be used by used to select some songs in the database and to automatically get a M3U list loaded into a player.
TorrentSniff reports current status information on a BitTorrent torrent including what files it contains and the current number of seeds (machines sharing the complete torrent) and leeches (machines still downloading the torrent). It is useful for comparing multiple potential sources of a file to find the best-seeded torrent.
pDonkeyS is Perl implementation of an eDonkey server. The main goal of the server is to provide framework for further eDonkey protocol exploration, but it could be useful in testing of client software, since the server can be configured to output very detailed debugging info about eDonkey traffic.
Glubs is a clubbing system similar to Yahoo! or MSN Groups. Users browse through a category-hierarchy and create clubs to share news, files, pics, links and a calendar with friends. Some of the core features are multi-language and -timezone support, and custom HTML templates/skins.