Taproot

Taproot is an upgrade to Bitcoin’s rules made up of three parts: Schnorr signaturesGlossarySchnorr signatureA digital signature scheme that Bitcoin introduced with Taproot in 2021, alongside ECDSA. Schnorr signatures are compact (64 bytes), provably secure and can be combined into a single joint signature.In the glossary →× (BIP 340), the Taproot rules (BIP 341) and the Tapscript scripting language (BIP 342). It has been active as a soft forkGlossarySoft forkA change to the consensus rules that only tightens them. Blocks that follow the new rules remain valid for old nodes – so Bitcoin can be developed further without a chain split, as with SegWit and Taproot.In the glossary →× since block 709,632 on 14 November 2021, after 90% of the blocks in a signalling period had signalled approval.^[1],[2]

Two ways to spend bitcoin

• Key path: a single signature, as in a normal payment.
• Script path: one of several predefined conditions, for example ‘after one year, a backup key may also spend’. Only the condition actually used is revealed.

As long as the key path is used, nobody can see whether other conditions existed at all.^[1] If all participants in a multisigGlossaryMultisig (multi-signature)A wallet in which several keys jointly control the bitcoin – for example 2 of 3. If one key is lost or stolen, the bitcoin stays safe. In return, setting it up and backing it up is considerably more demanding.On the learning path: Stage 6 · Step 4 – Inheritance & emergency plan →In the glossary →× setup jointly produce a single signature, it too is indistinguishable from a simple payment.^[3] This improves privacy and saves space.

Recognising Taproot

Taproot addresses start with bc1p and use the Bech32m format, an improved variant of the SegWit format (bc1q).^[4] Some older wallets can’t send to them yet. In everyday use, you pay as usual.

Taproot scripts are also used to write images and text into the blockchain (OrdinalsGlossaryOrdinals (inscriptions)A protocol that numbers individual satoshis and links them to content such as images or text (‘inscriptions’). Usable by anyone since January 2023; the data sits in Taproot scripts in the blockchain. Its usefulness is disputed.In the glossary →×). This is controversial; Forks & controversies explains both points of view.