The InterPlanetary File System (IPFS) is a hypermedia distribution protocol enabling the creation of completely distributed applications. One of the most efficient and effective ways to distribute information is through notifications, with a producer of content (publisher) sharing content with other interested parts (subscribers). IPFS already implements topic-based publish-subscribe systems under an experimental flag. The goal of this work is to advance on that, by developing a content-based pub-sub system (with subscriptions as predicates about event content) to disseminate information on top of IPFS in an efficient and decentralized way, leveraging its infrastructure. We design two protocols: ScoutSubs that is completely decentralized; FastDelivery that is centered in the publisher. With these two approaches, we show the different advantages of having each of these protocols simultaneously by comparing ScoutSubs’ full decentralization, and FastDelivery’s centralization at data sources.

The InterPlanetary File System (IPFS) is an hypermedia distribution protocol, addressed by content and identities. It aims to make the web faster, safer, and more open. The JavaScript implementation of IPFS runs on the browser, benefiting from the mass adoption potential that it yields. Startrail takes advantage of the IPFS ecosystem and strives to further evolve it, making it more scalable and performant through the implementation of an adaptive network caching mechanism. Our solution aims to add resilience to IPFS and improve its overall scalability, by avoiding overloading the nodes providing highly popular content, particularly during flash-crowd-like conditions where popularity and demand grow suddenly. We add a novel crucial key component to enable an IPFS-based decentralized Content Distribution Network (CDN). Following a peer-to-peer architecture, it runs on a scalable, highly available network of untrusted nodes that distribute immutable authenticated objects which are cached progressively towards the sources of requests.

The publish-subscribe paradigm is a wildly popular form of communication in complex distributed systems. The properties offered by it make it an ideal solution for a multitude of applications, ranging from social media to content streaming and stock exchange platforms. Consequently, a lot of research exists around it, with solutions ranging from centralised message brokers, to fully decentralised scenarios (peer to peer). Within the pub-sub realm not every solution is the same of course and trade-offs are commonly made between the ability to distribute content as fast as possible or having the assurance that all the members of the network will receive the content they have subscribed to. Delivery guarantees is something quite common within the area of centralised pub-sub solutions, there is, however, a clear lack of decentralised systems accounting for this. Specifically, a reliable system with the ability to provide message delivery guarantees and, more importantly, persistence guarantees. To this end, we present Pulsarcast, a decentralised, highly scalable, pub-sub, topic based system seeking to give guarantees that are traditionally associated with a centralised architecture, such as persistence and eventual delivery guarantees. The aim of Pulsarcast is to take advantage of the network infrastructure and protocols already in place. Relying on a structured overlay and a graph based data structure, we build a set of dissemination trees through which our events will be distributed. Our work also encompasses a software module that implements Pulsarcast, with our experimental results showing that is a viable and quite promising solution within the pub-sub and peer to peer ecosystem.

Permissionless computation is one of the missing pieces in the web3 stack in order to have all the tools needed to “decentralise Internet services”. There are already proposals to embed computation in decentralised networks like smart contracts, or blockchain networks for computational offloading. Although technically sound, their computational model is too restrictive to be used for general purpose computation. In this paper, we propose a general architecture of a decentralised network for general-purpose and permissionless computation based on content-addressing. We present a proof-of-concept prototype and describe in detail its building blocks.