What is Post-Quantum Cryptography?

Post-quantum cryptography is an encryption approach that aims to provide security in anticipation of the development of quantum computers. These computers can perform more powerful computations than regular ones and are believed to break existing cryptographic algorithm approaches. 

Post-quantum cryptography is also referred to as “quantum-resistant,” “quantum-proof,” or “quantum-safe” cryptography. Cryptographic experts started exploring the development of post-quantum cryptography around the 1990s after mathematician Peter Shor demonstrated that a quantum computer could easily crack public-key encryption.

Back then, the quantum computer was still theoretical. Large tech companies like IBM and Intel have invested billions of dollars in developing quantum computers in recent years. Post-quantum cryptography helps us protect our data when these quantum computers become available.

Other interesting terms…

• What is Cryptanalysis?
• What is a Quantum Computer?

Read More about “Post-Quantum Cryptography”

Post-quantum cryptography may sound complicated, but you only have to understand some relevant terms to grasp its meaning and significance.

What Is Post-Quantum Cryptography and What Concepts Are Relevant to It?

From the name itself, post-quantum cryptography involves two concepts—quantum and cryptography.

• Quantum: Quantum is a theory in physics that aims to explain the behavior and nature of matter and energy on the atomic and subatomic levels. When applied to technology, quantum helps create new ways of computing by harnessing the ability of subatomic particles to exist in more than one state. That means that unlike the computer bits we know today that can only represent either 0 or 1, quantum bits or qubits can take on both values at the same time. That translates to more powerful computing capability.

• Cryptography: Simply put, cryptography is the process of disguising information so that nobody else can read it. We currently use different forms of cryptography, and it helps prevent hackers from reading our data. For example, cryptography ensures that nobody else can see our bank account details when making an online payment or sending money to our family.

Post-quantum cryptography puts these concepts together. We need this type of cryptography when quantum computers become widely used.

What’s the Difference between Quantum and Post-Quantum Cryptography?

Most people confuse quantum cryptography with post-quantum cryptography. These are two different concepts despite sounding very similar.

As previously mentioned, post-quantum cryptography is any encryption algorithm that protects against cyber attacks involving the use of quantum computers. These encryption methods are intended to work on regular computers using complex mathematical problems, much like the cryptography we use today.

As such, post-quantum cryptography does not require special equipment. Post-quantum cryptography aims to make encryption work on mobile devices so all our data can be safe from quantum attacks. That lies at the core of what post-quantum is.

On the other hand, quantum cryptography uses quantum physics concepts to generate unbreakable encryption. Such a method requires heavy computing power, so specialized hardware is needed to implement it.

Why Is Post-Quantum Cryptography Important?

We’ve repeatedly heard how cybercriminals use increasingly sophisticated technology to attack entities and individuals. When quantum computers become widely available in the future, there is no stopping threat actors from harnessing their power.

Since quantum computers can perform fast and powerful computations, experts believe they can also crack public-key encryption. Online shopping, instant messaging, and other common Internet services may no longer be safe when that happens.

But attackers using quantum computers are not likely to target individuals primarily. According to the National Institute of Standards and Technology (NIST), if these attacks happen, the quantum computers will most likely be built by a nation-state and will aim to steal national security secrets.  

Now that we know what post-quantum is, we can understand how crucial it is in securing our data from attackers who will use quantum computers.

Can Quantum Computers Really Break Cryptography?

Several experts believe that quantum computers can crack modern encryption if they have enough qubits. In 2019, two quantum physics researchers published a paper suggesting that it could take eight hours for a quantum computer with 20 million qubits to break 2048-bit encryption.

While the study shows that quantum computers can break cryptography, we are still a long way from this possibility. IBM has just developed the first quantum computer that has more than 100 qubits in November 2021.

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While quantum computers today are still at the prototype stage, it doesn’t hurt to prepare, especially when it means securing sensitive data.