What Is the Concept of “Difficulty Adjustment” and How Does It Relate to Sudden Hashrate Spikes?

Difficulty adjustment is an automatic network mechanism that periodically changes the mining difficulty to ensure a consistent average block time, regardless of the total network hashrate. When a sudden hashrate spike occurs (like from a rental attack), the network's block time temporarily drops significantly.

The difficulty adjustment will then raise the difficulty level to compensate, bringing the block time back to the target. This mechanism is the network's natural defense against sustained hashrate attacks.