Every time you make a secure connection over the internet – to your bank, to Facebook, or nearly anywhere online – cryptography is what keeps that communication secure. Some of that cryptography is based upon mathematical problems known to be solvable by a quantum computer. As the scientists working on quantum computers continue to make progress, cryptographers are at work as well, developing new post-quantum cryptosystems based upon mathematical problems which we believe are resistant to quantum attacks.
When it comes time, migrating all network traffic, including communications from services and applications, to new post-quantum cryptography will be a time-consuming and lengthy process. Fortunately, we have some time. Even the most optimistic estimates are that it will be five or more years before a sufficiently powerful and stable quantum computer capable of breaking today’s public-key cryptography is running.
Digital Transformation, PKI and Shor’s algorithm
Everyone talks about digital transformation. Almost none of them is aware that in 5 years quantum computers will probably have the potential for breaking private keys used for digital signatures.
The problem is that digital transformation relies on PKI cryptography mechanism. What will happen when someone rewrite and change original digital document and sign it again with original private key? Non-repudiation will not exist anymore.
In that time we will probably use another cryptography algorithms (quantum criptography), but for all older documents that were signed with PKI the authenticity will be repudiated.