(CoinTelegraph) Computations previously thought to be functionally impossible due to their incompatibility with traditional computing are now becoming only a matter of time for quantum computers.At the moment, blockchains’ cryptographic functions are considered to be secure, given that breaking them would need massive computing resources that cannot be achieved with classical computers. However, a quantum computer would be able to break this kind of cryptographic shield in a matter of days.
Quantum computing is not a threat to the blockchain as a concept per se but to the projects that use the technology. While present-day quantum computers cannot break blockchains and their underlying cryptography, larger ones on the horizon are a threat, indeed, and need to be prepared for.
Powerful quantum computers might become a threat to all blockchains that rely on the ECDSA (Elliptic Curve Digital Signature Algorithm), including Bitcoin and Ethereum.
There are two main approaches to address the potential quantum threats: whether to create a quantum-resistant layer to an existing blockchain protocol to increase its security or create a quantum-resistant blockchain from scratch.
Back in 2017, Andreas Antonopoulos said that we should be ready for a major upgrade in Bitcoin when it becomes clear that quantum computers can break the elliptic curve. Nevertheless, it would be reasonable to consider upgrading before the first signs of potential threats show up.