Content Interchange Identifiers (CIDs) are a fundamental building block of the InterPlanetary File System (IPFS), a distributed file system that aims to make the web faster, safer, and more open. CIDs are used to uniquely identify and locate content within the IPFS network, and play a crucial role in enabling IPFS to achieve its goals of decentralization, immutability, and scalability.
The CID format is based on a multihash, which is a self-describing hash that includes the hash algorithm and its output in the same data structure. This allows the IPFS network to easily identify the hash algorithm used to calculate the CID, and eliminates the need for separate metadata to store this information. The CID structure is also designed to be flexible and extensible, allowing for future changes to the IPFS protocol without breaking backwards compatibility.
The CID computation process involves taking the input content and applying a hash function to it, resulting in a unique identifier that represents the content. This process is performed by the IPFS node that is responsible for storing the content, and the resulting CID is then used to reference the content within the IPFS network. The CID can also be used to verify the integrity of the content, as any changes to the content will result in a different CID being calculated.
In addition to its role in content identification and location, CIDs also play a crucial role in enabling the IPFS network to achieve its goal of scalability. CIDs are designed to be content-addressable, meaning that they are based on the content itself rather than its location. This allows IPFS to perform distributed content-based routing, allowing nodes to efficiently locate and retrieve content without the need for a centralized index or directory.
In conclusion, CIDs are a fundamental building block of IPFS that play a crucial role in enabling the network to achieve its goals of decentralization, immutability, and scalability. Understanding the format, structure, and computation of CIDs is essential for anyone looking to work with IPFS and take advantage of its powerful features.