That means they could create an enormous security headache if they are used to crack the encryption that currently secures everything from emails and medical records to bank transactions.
As research into quantum computers has progressed in recent years, governments and tech companies have realised that if someone does build a large-scale quantum computer, then a new quantum-resistant form of encryption will need to be ready and waiting.
The National Institute of Standards and Technology (NIST), the US federal agency that oversees technology standards, is now taking the first steps toward developing quantum-resistant crypto.
NIST is asking for comments on a new process to find and evaluate public key cryptographic algorithms that can't be cracked by quantum computers.
