A nonce is a number added to a hashed or encrypted block in a blockchain. It is a number that is only used once in a blockchain transaction to ensure that the transaction is unique and cannot be replicated. [1]
The nonce is a critical component of the blockchain mining process. Miners must find a nonce that, when combined with the other data in the block (such as the timestamp, transaction data, and previous block hash), results in a hash value that meets the network's difficulty target. [1] This process of finding a valid nonce is known as "proof of work" and is what secures the blockchain against attacks.
