Mastering Blockchain - Second Edition

Distributed Hash Tables

A hash table is a data structure that is used to map keys to values. Internally, a hash function is used to calculate an index into an array of buckets from which the required value can be found. Buckets have records stored in them using a hash key and are organized into a particular order.

With the definition provided earlier in mind, one can think of a DHT as a data structure where data is spread across various nodes, and nodes are equivalent to buckets in a peer-to-peer network.

The following diagram shows how a DHT works. Data is passed through a hash function, which then generates a compact key. This key is then linked with the data (values) on the peer-to-peer network. When users on the network request the data ...