👉 In the context of cryptography, a "headshake" is a cryptographic protocol used to verify the identity of a user. It involves two parties who are connected by a shared secret key and must exchange their public keys in order to authenticate each other. The process typically starts with one party asking for a single authenticated message from another party, which they then send back to the first party. This is repeated until both parties have exchanged their messages, at which point the first party can verify that the second party