The InterPlanetary File System (IPFS) is a peer-to-peer (P2P) hypermedia protocol designed to make the web faster, safer, and more open. It aims to replace HTTP, the backbone of today's web, by changing how we locate and move data. Instead of location-based addressing (where files are found by their server location), IPFS uses content-based addressing (where files are found by their content).

Core Concepts of IPFS

Understanding IPFS requires grasping a few fundamental ideas:

1. Content Addressing & Content Identifiers (CIDs)

In IPFS, every piece of content (a file, a directory, or even a small chunk of a file) is uniquely identified by a cryptographic hash of its content. This hash is called a Content Identifier (CID). If the content changes, even by a single bit, the CID changes. This has powerful implications:

• Immutability: Once content is added to IPFS and identified by its CID, it cannot be changed without changing the CID. This ensures data integrity.
• Verification: You can verify that you have the correct content by hashing it and comparing it to the requested CID.
• Deduplication: Identical files will have the same CID, meaning they are stored only once on the network, saving space.

Thinking about unique identifiers for data, one might also consider how FinTech solutions use unique IDs for transactions and secure data handling, though the underlying technology differs.

2. Merkle DAGs (Directed Acyclic Graphs)

IPFS uses a data structure called a Merkle DAG. Large files are broken down into smaller chunks (blocks). Each block gets its own CID. Then, a "parent" object is created that links to all these blocks, and this parent object also gets a CID. If a file is part of a directory, the directory object (which also has a CID) links to its files and subdirectories in a similar manner.

This structure allows for:

• Efficient data structuring: Linking data objects together in a graph.
• Tamper-resistance: Any change in a block would change its CID, which would change the parent's CID, and so on, up to the root CID of the entire dataset.
• Version control: Similar to Git, changes to files create new objects with new CIDs, allowing access to previous versions.

3. Distributed Hash Table (DHT)

So, how does IPFS find content given its CID? This is where the Distributed Hash Table (DHT) comes in. The DHT is like a massive, decentralized lookup table spread across all the IPFS nodes on the network. When a node wants to find content, it asks its peers in the DHT, "Who has the content for this CID?" Peers that have the content or know who has it will respond with the provider records (IP addresses and node IDs).

The DHT enables IPFS to locate content without relying on centralized servers. Each node only needs to store a small part of the DHT routing information.

4. IPNS (InterPlanetary Naming System)

While CIDs provide permanent, verifiable links to content, they are not very human-friendly (e.g., QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1mXWo6uco). Also, if you update your website, its root CID will change, and you'd need to share a new CID every time. IPNS solves this by allowing you to create mutable pointers (like domain names) to CIDs. An IPNS name is the hash of a node's public key. The node can then sign a record that associates its IPNS name with a specific CID. This record can be updated, allowing you to have a stable address for content that changes over time.

These core concepts work together to create a decentralized system where content can be found, verified, and shared efficiently and resiliently. Understanding these building blocks is key to appreciating the power and potential of IPFS. Explore how IPFS works for a more technical dive.