Most bitcoin transactions requires a valid digital signature to be included in the blockchain, which can only be generated with a secret key; therefore, anyone with a copy of that key has control of the bitcoin. The digital signature used to spend funds is also referred to as a “witness”, a term used in cryptography. The witness data in a bitcoin transaction testifies to the true ownership of the funds being spent.

Mastering Bitcoin - PROGRAMMING THE OPEN BLOCKCHAIN

by Andreas M. Antonopoulos

#masteringbitcoin #16