Nonce: Concept and Application in Mining

Nonce is an abbreviation of the phrase "number used once", which translates from English as "number used once". Simply put, it is a counter that increases under certain conditions. As the name suggests, this counter is used only once in the action for which it is intended.

The nonce component is used not only in BTC. For example, Ethereum has two different nonces that are used in blocks and for both types of accounts.

The main purpose of introducing nonce into BTC is to introduce randomness. This is important for mining. As we know, mining requires many recalculations of the block contents. If the hashing results satisfy the requirements, then the mining process is successful. Unfortunately, it is very difficult to get the correct hash result in one try.

Ethereum uses the two nonces differently. The first application is the same as in BTC. Nonce is a standard component of Ethereum blocks. The second application concerns multiple transactions for a single account.

Another important application of nonce is workload distribution of mining pools. Each mining pool should avoid mining the same blocks multiple times at the same time. This can be achieved in several ways. The pool coordinator can avoid sending timestamps, send a set of different transactions to different participants, or issue nonce ranges to different participants.

The first approach is risky because all pool members work at approximately the same time. The second approach requires a lot of extra work to be done by the pool coordinator. Therefore, the latter approach is the most effective.