Understanding Retargeting in Proof-of-Work Blockchains
In PoW blockchains, miners compete to solve complex equations or puzzles to create new blocks.
However, the difficulty of these puzzles increases over time.
Mining, Consensus, and Retargeting
Miners strive to be the first to solve the puzzle and receive the associated reward.
To determine the block’s hash value and validate transactions, miners repeatedly utilize the SHA-256 hashing function, modifying the nonce until the resulting hash value is below the target.
However, retargeting adjusts this target approximately every 14 days, or every 2016 block.
Retargeting ensures that the average block generation time, typically 10 minutes, is maintained by increasing the puzzle’s difficulty.
This adjustment is achieved by dividing the hash target of the first block in the retargeting period by the hash target of the current block.
Constant retargeting in PoW blockchains means that more computational power is required by miners today compared to when Bitcoin was first created in 2009.