Imagine a padlock hanging on a public fence. Anyone can walk up and study it. Today, staring at the lock does not give a thief a working key. That is the bargain behind the cryptography that secures most cryptocurrencies. A future quantum computer could look at the lock already sitting on the blockchain and cut a key that gives an unauthorized third-party access to someone else’s coins.
That lock is elliptic curve public key cryptography (ECC). Cryptocurrency networks such as Bitcoin, Ethere
