Quantum-Safe Encryption - Sci-Fi or Significant?

It sounds like something from a sci-fi movie but making sure you’re ready for the post-quantum computing era is important today. Pro-active security is fundamental when it comes to personal data, but the realities of quantum computing mean that current standards are likely to be insufficient for sensitive information.

The more tech savvy / digital native amongst us will keep an eye out for the padlock in the address bar, giving confidence that communication is secure between you and the host. This is accurate for current levels of computing power where it would take three-hundred trillion years to ‘brute force’ a RSA 2048-bit key, but woefully inadequate against the future quantum computers that will be able to do the same task in just ten seconds.

What does Brute Force mean?

This is an approach where a computer is used to rapidly attempt all possible combinations of a password, username, etc. For instance trying to guess your 4-digit pin number by trying 0001, 0002, 0003… all the way to 9999. As computers have become more advanced we moved to public-key encryption methods such as RSA which dramatically increase the number of possible keys and therefore make it impractical to try a brute force attack. 

Do quantum computers exist?

Yes, but not to the power that is needed to quickly break current encryption standards. The ten second figure quoted above is for a quantum computer with 4099 qubits (qubits are a measure of how powerful a quantum computer is), currently the most powerful chip in existence is IBM’s Condor with 1,121 qubits but they hope to build a 100,000 qubit system by 2033. Given the rate of development we need to be preparing for the post-quantum computer era now.

Why can’t we move to quantum-safe encryption once quantum computers exist?

In reality this is what many organisations and smaller businesses will do, but there are some key elements to bear in mind when managing sensitive information. The cost of storing data is very, very low so there is not a large financial hurdle to stealing encrypted information today, and then waiting five to ten years to easily decrypt it. 

There is a vast amount of information on the internet, but if you were to deliberately target banks, healthcare providers, insurance companies, etc but skip out your public social media websites then there would be a much higher likelihood of a financial return.

It’s important to think… is this information going to be valuable in ten years time? Is it going to change? Could it be used to compromise my online or offline identity? Obvious answers would be full name, date of birth, addresses, bank account numbers, sort codes, national insurance numbers, social security numbers, passport details, etc.

What can be done today?

The vast majority of data at rest (sitting on a hard-drive somewhere) is encrypted to a high enough standard for the post-quantum era (typically SHA-256) - cloud providers will typically have encryption activated as standard. The more pressing issue is data in transit - for instance from your computer to a company’s server, the industry-standard level of encryption will not be sufficient for the post-quantum era.

The US Government’s National Institute of Standards and Technology announced CRYSTALS-KYBER as the only recommended encryption protocol for this purpose. 

When a client interacts with a website, the server will generate a secret key and a public key, the secret key will never leave the server but the public key will be sent to the client. On arrival the public key will be used to generate the first secret symmetric key and an encapsulated version. The encapsulated version is sent back to the server where it can be decrypted using the secret key to get the second copy of the secret symmetric key. We now have a secret symmetric key on the client’s device and the server, without having shared it over the web. We can now encrypt and decrypt messages easily between the two using quantum-safe encryption protocols like AES-256.

Who is using CRYSTALS-KYBER?

We take the integrity of your data seriously at Pyrexia so we implemented CRYSTALS-KYBER last summer, a few months later Signal incorporated it into their existing encryption protocol (check it out here). There will be others out there using it, but it’s something that should start to enter your online security awareness.