IPFS - Content Addressed, Versioned, P2P File System (1407.3561v1)

Abstract: The InterPlanetary File System (IPFS) is a peer-to-peer distributed file system that seeks to connect all computing devices with the same system of files. In some ways, IPFS is similar to the Web, but IPFS could be seen as a single BitTorrent swarm, exchanging objects within one Git repository. In other words, IPFS provides a high throughput content-addressed block storage model, with content-addressed hyper links. This forms a generalized Merkle DAG, a data structure upon which one can build versioned file systems, blockchains, and even a Permanent Web. IPFS combines a distributed hashtable, an incentivized block exchange, and a self-certifying namespace. IPFS has no single point of failure, and nodes do not need to trust each other.

• The paper presents a novel peer-to-peer file system that uses content addressing and a Merkle DAG structure to ensure secure, versioned data storage.
• The methodology combines proven protocols from BitTorrent, DHTs, and Git to achieve efficient lookup and reliable data exchange across millions of nodes.
• Strong numerical results and a scalable design underscore IPFS's potential to transform decentralized data distribution and future web infrastructure.

Overview of "IPFS - Content Addressed, Versioned, P2P File System (DRAFT 3)"

The paper presents the InterPlanetary File System (IPFS), detailing its architecture, components, and potential applications. IPFS aims to create a unified system connecting all computing devices into a peer-to-peer distributed file system. The system is built on robust concepts from established protocols like Distributed Hash Tables (DHTs), BitTorrent, Git, and self-certifying file systems (SFS), synthesizing them into a cohesive architecture designed to enhance data distribution, versioning, and availability.

Core Components and Architecture

IPFS is structured around several key sub-protocols that collectively enable its functionality:

1. Identities: Nodes are identified using a public-key-based system inspired by S/Kademlia. This provides cryptographic assurance of node identities and forms the basis for secure peer interactions.
2. Network: The network layer allows IPFS nodes to communicate over various protocols, including WebRTC and uTP for efficient and reliable data exchange.
3. Routing: Leveraging a DSHT based on Kademlia and Coral, IPFS maintains peer and object metadata, facilitating efficient peer discovery and object retrieval.
4. Block Exchange (BitSwap): This protocol underpins the data distribution mechanism, allowing nodes to barter blocks of data in a persistent marketplace. It features a credit-based system to incentivize participation and mitigate freeloading.
5. Object Merkle DAG: The core data structure is a generalized Merkle Directed Acyclic Graph (DAG), which ensures content addressing, tamper resistance, and deduplication. This structure supports various data formats and is crucial for building complex systems like file hierarchies and blockchains.
6. Files: The file subsystem imitates Git’s object model, enabling versioned filesystems. It includes structures for handling file splitting, path resolution, and efficient lookup.
7. Naming (IPNS): IPFS introduces a mutable namespace analogous to DNS but decentralized and cryptographically secure. This enables persistent, human-readable names that can reference mutable states.

Strong Numerical Results and Bold Claims

Key numerical highlights and bold claims in the paper include:

• Efficiency of Kademlia: Lookup queries contacting $\ceil{\log_2 (n)}$ nodes on average, scaling efficiently even with millions of nodes.
• BitSwap's Debt Ratio Performance: A probabilistic function ensuring a high probability of block exchange cooperation until the debt surpasses twice the credit, which effectively balances load and prevents exploitation.
• Scalability: Reference to BitTorrent's ability to handle networks of over 20 million nodes suggests IPFS’s potential in achieving similar, if not greater, scalability.

Implications and Future Directions

Theoretical Implications:

• Merkle DAG Evolution: The use of a generalized Merkle DAG beyond Git opens avenues for developing highly efficient and secure distributed data structures.
• Decentralized Naming Systems: Extending the concepts from SFS, IPNS presents a model for decentralized web naming, reducing reliance on traditional DNS infrastructure.

Practical Implications:

• Data Redundancy and Availability: Addressing the persistence problem by ensuring copies of data are widely distributed across participating nodes.
• Versioned and Encrypted Content Distribution: Facilitating the secure and persistent distribution of data while maintaining its history.

Future Developments in AI and Networking:

• Efficient Data Storage and Retrieval: IPFS can provide a foundation for AI systems requiring access to vast, versioned datasets, ensuring data integrity and accessibility.
• Evolving Internet Infrastructure: By enhancing protocols for decentralized data distribution and storage, IPFS could play a significant role in the future web, particularly in how content is served and maintained.

In summary, the IPFS proposes an integrated peer-to-peer distributed file system with strong theoretical foundations and practical implications, potentially influencing the future landscape of internet infrastructure and large-scale data management.