Nonce

Written by Aidan Mott

Introduction

A nonce is an arbitrary 32-bit random number that serves as a component of the hash that makes up the structure of a Bitcoin block. The process of miners calculating and transmitting the correct nonce is what makes up proof-of-work.

Each new Bitcoin block is comprised of transmitted transactions, the coinbase transaction, timestamp, previous block hash, merkle root, and finally the nonce. In order to add a new block miners must find the correct nonce through brute force calculations.

The target in the Bitcoin blockchain is a 256-bit number representing the hash that meets the current mining difficulty level. As the difficulty increases the lower the target becomes, and vice versa as the difficulty decreases. This means that the constant competition of miners to find a nonce that is lower than the current target, is regulated by the difficulty level to average the 10 minute period between blocks.

Suggested Reading

Decoding the enigma of Bitcoin Mining by Kieran Vaidya

What Is a Nonce? A No-Nonsense Dive into Proof of Workby Ben Whittle

If there is anything you'd like to add or change, you can tweet your feedback at @messari_crypto or email jack@messari.io