Are there encryption methods that quantum computers won’t be able to break?
Yes, because there are mathematical problems that are just as difficult for quantum computers to solve. Cryptography experts are currently building cryptographic schemes based on these problems.
This type of encryption is called post-quantum cryptography (PQC).
The National Institute for Standards and Technology in the U.S. (NIST) is already certifying post-quantum encryption methods for various applications. I expect these NIST standards will be adopted throughout the industry.
Can the encryption methods we’re using today be made quantum-resistant?
Some encryption methods that are currently in use are particularly vulnerable to future quantum computers.
For instance, a method called RSA encrypts a large portion of internet traffic. It uses prime factors which are hard for traditional computers to decode but much easier for quantum computers. Organizations will need to replace RSA before a sufficiently powerful quantum computer is released.
The good thing is that there are several ways to do this. Current RSA encryption uses 2048 bits, but doubling the number of bits makes it difficult even for quantum computers to crack.
The same goes for other encryption schemes. Just by increasing the problem size, you can make it much harder to solve.
Some actors are already harvesting data to decrypt in the future. What does this mean?
“Harvest now, decrypt later” is the principle of storing encrypted data until there are methods available to decrypt it.
Some powerful players have deep access to internet traffic data and extensive storage capabilities. They save data they can’t decrypt right now and plan to crack the encryption when new technology — like a powerful quantum computer — becomes available in the future.
The data they’re storing might be old by then, but it can still be critical. Think of intelligence services, for example.
That’s why developing post-quantum encryption is already relevant, even though current quantum computers aren’t powerful enough.
Most internet users today value their privacy. Therefore, as IT professionals, we need to ensure our encryption protects their personal data, even from these types of attacks.
But also keep in mind that you need to store huge amounts of data, if you’re planning such an attack. This is very expensive, so it’s unlikely that attackers save information that isn’t particularly relevant to them. That’s why this might only affect very few people.
How can businesses prepare for the arrival of powerful quantum computers?
If you work in IT, it’s good to identify where you use encryption in your company.
Start with sensitive areas, like VPN, external server access, or remote access. Determine which cryptographic methods you’re using and think about how you could implement post-quantum standards in the future.
I expect most operating systems to deploy post-quantum safe crypto libraries in the upcoming years. Your browser will be able to use those libraries to protect your browsing data. So, make sure all your software is patched and up to date.
If you provide web services to your customers or employees, you might want to ensure they’re also compatible with these crypto libraries.