Taproot

Taproot is a major upgrade to the Bitcoin protocol, activated in November 2021. It introduced Schnorr signatures and Merkelized Abstract Syntax Trees (MAST), which improve Bitcoin's privacy, efficiency, and smart contract capabilities. Taproot makes complex transactions (such as multisig and time-locked transactions) look identical to simple payments on the blockchain, enhancing privacy. It also reduces transaction sizes and fees for advanced transaction types.