Wikipedia
Bencode
Bencode (pronounced like B encode) is the encoding used by the peer-to-peer file sharing system BitTorrent for storing and transmitting loosely structured data.
It supports four different types of values:
- byte strings,
- integers,
- lists, and
- dictionaries (associative arrays).
Bencoding is most commonly used in torrent files. These metadata files are simply bencoded dictionaries.
While less efficient than a pure binary encoding, bencoding is simple and (because numbers are encoded as text in decimal notation) is unaffected by endianness, which is important for a cross-platform application like BitTorrent. It is also fairly flexible, as long as applications ignore unexpected dictionary keys, so that new ones can be added without creating incompatibilities.