Key Path Spend in Taproot

Published by Mario Oettler on

A Key Path Spend is very similar to the above mentioned spend with a raw public key.

In Taproot, Q (the witness program) is slightly different. It is a 32 bytes long value that represents the public key according to BIP340 (Schnorr Signatures). The big difference to a raw public key spend is that the public key is tweaked with a value T.

In order to spend the coins from the tweaked public key, you need to provide a signature based on the private key and the tweak t.

You find this part in the output of a transaction. The following figure illustrates it: