Kademlia is a DHT protocol which offers a number of desirable features not simultaneously offered by any other DHT. It makes sure that there are minimum lookup messages sent to locate a node. The algorithm resists various denial-of-service attacks. Each node is associated with a 160-bit long node ID via which each node is located. The distance between any two nodes with ID’s x and y is given by x XOR y. The lookup algorithm in kademlia successfully located closest nodes to any node-ID, converging to the target in logarithmic steps.
The Kademlia protocol consists of 4 RPC’s:
- PING checks if a particular node is online.
- STORE instructs a node to store a <key,value> pair for later retrieval
- FIND NODE takes a 160-bit node ID as parameter and returns the k-closest nodes it thinks are the nearest to the node.
- FIND VALUE takes a node-ID as well as key as parameters. If there has been a STORE operation on that key on the parameter node then it returns that stored value, else it works exactly the same as FIND NODE.
An example example.cfg configuration file can be found in the main directory.
- To compile the sources, invoke:
make
- To compile the API documentation, invoke:
make doc
- To run the code, invoke:
make run
- To run all the previous command in this order, invoke:
make all