Nonce

Nonce stands for Number Only Used Once. In the context of cryptocurrency. They are 32-bit random numbers serving as the final piece of the puzzle miners need to discover. To have their candidate blocks added to a blockchain.

Candidate blocks are formed by combining the previous block’s hash, root hash for current transaction data and nonce. The objective for miners is to find a nonce. That in combination with the prior block hash and root hash is accepted by the blockchain as valid. So their candidate block is added to the chain and they receive the block reward.

The difficulty level determines how challenging it is for miners to discover a valid nonce that is accepted by the network. Dictating the amount of hash power that needs to be applied to the task.

Further Reading Nonce

The Significance of Nonce in Blockchain