What Is the InterPlanetary File System?

The InterPlanetary File System, abbreviated IPFS, is a peer-to-peer protocol for storing and retrieving files by the hash of their contents rather than by the location of a server. A client that wants a file supplies a content identifier, and the network locates any peer currently holding a block matching that identifier. The design was introduced by Juan Benet in 2014 and is maintained as an open specification and reference implementation, with the original description published as the IPFS content-addressed peer-to-peer file system paper.

Its intellectual lineage runs through several earlier systems. Distributed hash tables from Kademlia provide peer routing, the Merkle directed acyclic graph structure comes from Git and from cryptographic hash trees, and the block exchange strategy borrows from BitTorrent. What IPFS adds is the combination: a single addressing scheme that spans files, directories, and versioned data structures, layered over a modular transport stack.

Content Addressing and Data Structures

A file added to IPFS is split into blocks, each block is hashed, and the hashes are assembled into a Merkle DAG whose root hash identifies the whole object. That root is encoded as a content identifier, a self-describing label that carries the multihash of the data along with codec and version fields so that different hash functions and encodings can coexist. Content addressing has two consequences that shape the rest of the system. Retrieval is verifiable, since a client can hash what it receives and confirm the result matches what it asked for, and identical data added independently by different users produces one identifier, giving deduplication for free. It also means addresses are immutable: changing a byte changes the identifier, so mutable naming is handled separately by the InterPlanetary Name System, which maps a public key to a signed pointer at a current root hash.

Networking and Block Exchange

Peer discovery, transport negotiation, encryption, and multiplexing are handled by libp2p, a modular networking stack that was factored out of IPFS and is now used by other distributed systems. Content routing relies on a Kademlia distributed hash table in which providers advertise the identifiers they hold, supplemented by local network discovery and by delegated routing services for constrained clients. Blocks move over Bitswap, a want-list protocol in which a node announces the blocks it needs and sends blocks it has to peers that need them. Unlike BitTorrent, Bitswap has no tit-for-tat enforcement in its deployed form, so persistence depends on pinning by interested nodes or on paid storage arrangements rather than on protocol-level incentives.

Operational Behavior and Security

Measurement studies of the public network have documented behavior that a formal specification does not capture. Because any peer can announce any identifier, the network is exposed to content eclipse and routing pollution, and analyses of malicious and misbehaving IPFS nodes have cataloged nodes that flood the DHT or serve mismatched blocks. Data on IPFS is public by default: an identifier is an unencrypted pointer, so confidentiality requires encrypting content before it is added. Content moderation is difficult for the same reason that censorship is, since removal requires cooperation from every node pinning the data, which is why most public access happens through HTTP gateways where policy can be applied.

Applications

The InterPlanetary File System has applications in a range of areas, including:

• Decentralized web hosting and distribution of static site content
• Storage of non-fungible token metadata and blockchain-adjacent assets
• Package and container image distribution across edge or bandwidth-limited networks
• Archival and scientific dataset publication with verifiable integrity
• Offline-first and mesh network file sharing in low-connectivity regions