This is new info to me. Forgive my ignorance about quantum computers, but how will it be a huge threat to blockchain? i mean, i just can't see the point why blockchain will be vulnerable. I thought people are aiming to improve it?
There are a lot of threads on Bitcointalk about the threat of quantum computers on bitcoin.
http://lmgtfy.com/?q=quantum+site%3Abitcointalk.orgThe gist of the matter is that quantum computers can break ECDSA which bitcoin uses for digital signatures and will be theoretically able to calculate private keys from public keys.
This is prevented by not reusing addresses because addresses are not public keys but a hash of them and quantum computing can't do anything with them. (An address's public keys are exposed whenever a transaction is made with that address)
However this is not a significant threat as quantum computing isn't that advanced yet, there are better easier targets than bitcoins (or other cryptocurrencies), and bitcoin can always move to a quantum resistant algorithm.