PDTP: the Peer Distributed Transfer Protocol

Architecture and Background

Tony Arcieri, PDTP :The Peer Distributed Transfer Protocol Despite decades of evolution, Internet file transfer is still plagued with problems to which formalized solutions are either inadequate or nonexistent. Lack of server-side bandwidth often renders high demand content inaccessible (which we affectionately refer to as the Slashdot effect).

Vulnerability Analysis

When the ability of a single server to provide content is exceeded, manual mirror selection is often utilized, providing an unnecessary and often problematic experience for end users. No formalized cryptographic mechanism exists for preventing tampering of files located on a particular server, and consequently malicious individuals have managed to place trojans in the releases of many high profile open source applications.

Exploitation and Demonstrations

The Peer Distributed Transfer Protocol (PDTP) aims to solve all these problems. PDTP can either function with a network of servers providing content directly to clients, or can provide BitTorrent-like download swarming, by forcing clients to participate in file transfers.

Remediation and Defensive Strategies

PDTP includes built-in mechanisms to prevent file tampering through the use of the Digital Signature Standard, and is able to automatically verify that a given file has been signed by a DSA key with a complete x.509 certificate check to ensure a given certificate can be trusted. PDTP also provides a UDP-based decentralized search mechanism which, unlike current systems such as FastTrack, Gnutella, or FreeNet, does not consume undue bandwidth or system resources, all while removing legal liability for content indexing from the central services being utilized as entry points to the search system. Tony Arcieri is a system administrator and programmer for the Pielke Research Group and Colorado Climate Center at Colorado State University. He has also contributed to a number of open source projects, including authoring the Ogg Vorbis plugin for XMMS, the cdcd and gdcd X11 CD player applications, and various contributions to other projects such as the Subversion version control system and the FreeBSD operating system.