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Kademlia Explained

August 20, 2021

Edited October 17, 2021

What is Kademlia?

Kademlia is a distributed hash table for decentralized peer-to-peer computer networks.

What is "peer-to-peer"?

Typical networks are based on the client-server model, in which clients make requests to a service from a centralized server.

Now, a peer-to-peer network contains nodes, or peers, who can share information with one another without the need for a centralized server.

What's so special about Kademlia nodes?

Let's go over some properties of a node. First, they are assigned a 160-bit opaque ID. By opaqueness, we mean that the ID contains information about the node instead of hodgepodge of numbers, letters, and symbols.

A node also contains an address. This address is helps other nodes connect to it in the network and it find other nodes with its third component: a routing table.

Routing tables

A routing table is the data structure which keeps information about the other nodes to contact. In short:

The ID tells us who this node is, the address tells us where this node is, and the routing table tells us how to contact others.

A familiar friend: binary trees



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