IPFS - Content Addressed, Versioned, P2P File System

Reference: Juan Benet (2014). arXiv:1407.3561 (DRAFT 3). Source file: downloads/ipfs_benet.pdf. URL

Summary

Original whitepaper introducing the InterPlanetary File System (IPFS), a peer-to-peer hypermedia protocol that synthesises ideas from Git (Merkle-DAG object model), BitTorrent (incentivised block exchange via BitSwap), DHTs (Kademlia-based routing), and self-certifying file systems (SFS) into a single content-addressed distributed file system. Objects are referenced by the cryptographic hash of their contents, giving intrinsic integrity, deduplication, and location independence.

The design stack layers an identity/peer-routing layer (S/Kademlia DHT), a block exchange layer (BitSwap with tit-for-tat credit), an object graph layer (Merkle-DAG with links), a naming layer (IPNS for mutable pointers signed by keys), and application-level filesystem semantics. The paper positions IPFS as the substrate for a “permanent web” where content survives independent of any particular host.

Key Ideas

  • Content addressing: name = hash(content) -> intrinsic integrity, dedup, cacheability
  • Merkle-DAG as universal object model spanning files, directories, commits
  • BitSwap: BitTorrent-like block trading generalised beyond single swarms
  • Kademlia DHT for peer and content routing
  • IPNS: mutable pointer namespace via signed records keyed to public keys
  • Self-certifying paths and location-independent fetching

Connections

Conceptual Contribution

  • Claim: A single peer-to-peer protocol layered over Merkle-DAG content addressing can unify the roles played today by HTTP, Git, BitTorrent, and CDNs, yielding a permanent, decentralised, versioned web.
  • Mechanism: Five-layer stack — S/Kademlia DHT for identity/routing, BitSwap for incentive-compatible block exchange, Merkle-DAG for the object graph, IPNS for mutable naming via signed records, and filesystem-level conventions above that. All objects are referenced by their SHA-2 multihash, so any peer can serve any object and clients can verify it independently.
  • Concepts introduced/used: Content-addressed Storage, Merkle-DAG, Gossip Protocols, BitSwap, IPNS, Self-certifying paths, Peer Sampling Service, Hypermedia
  • Stance: engineering / systems
  • Relates to: Directly underpins the distribution story for Protocol Documents in A Scalable Communication Protocol for Networks of LLMs — Agora PDs are hash-identified and can be served over any content-addressed store, of which IPFS is the canonical example. Shares the decentralised-naming motivation with Decentralized Identifiers and the self-organising-overlay motivation with Myconet Fungi Inspired Superpeer Overlay.

Tags

#content-addressing #p2p #distributed-systems #protocols #merkle-dag

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