Transactions on a blockchain have to be signed with a private key. This makes sure that people can only spend coins if they have the private key of their wallet.
In this video we will refactor our Javascript blockchain so that it will only accept signed transactions.
We’ll use the secp256k1 elliptic curve to generate a keypair. The same algorithm used in Bitcoin. But you can use other algorithms as well.
![Entrevista Leif Ferreira – Meetup Pioneros Bitcoin [SUBS FR – PT]](https://tv.bit2me.com/wp-content/uploads/2019/07/entrevista-leif-ferreira-meetup-277x156.jpg)
