How Quantum Computers Break The Internet... Starting Now

Currently, various nation states and individual actors are intercepting and storing a large amount of encrypted data, including passwords, bank details, and social security numbers. However, they are unable to decrypt these files.

So why are they engaged in this activity? The reason is their belief that within the next 10 to 20 years, they will have access to quantum computers capable of breaking encryption within minutes.

This practice is referred to as Store Now, Decrypt Later (SNDL). Its effectiveness lies in the fact that certain information available today will remain valuable in the future, such as industrial and pharmaceutical research, top secret government intelligence, and other sensitive data. This threat is widely recognized, including by the National Security Administration, which states that a sufficiently large quantum computer, if developed, could undermine widely deployed public key algorithms.

In the next five to ten years, quantum computing is expected to render current encryption methods obsolete. Consequently, the United States Congress has passed legislation mandating government agencies to transition immediately to new cryptographic methods that are resistant to attacks by quantum computers. Traditional encryption schemes have been remarkably successful for over 40 years.

Prior to the 1970s, exchanging private information required a physical meeting to share a secret key, which was then used for encryption and decryption—a process known as symmetric key algorithm. As long as the key remained secure, the messages were considered safe.

However, the need for secure communication with unfamiliar parties and the difficulty of arranging in-person meetings posed challenges. In 1977, three scientists—Rivest, Shamir, and Adelman—developed a groundbreaking encryption method, now known as RSA (named after their initials). RSA involves each person having two large prime numbers, kept secret, which are multiplied together to generate a larger number made public for others to see.

When sending a private message, the sender utilizes the recipient's public number to scramble the message in such a way that it becomes impossible to unscramble without knowledge of the two prime factors. This approach, known as asymmetric key encryption, enables the intended recipient to decode the message easily while preventing others from doing so unless they can factor the large public number. Factoring such numbers with traditional computers is incredibly time-consuming, but quantum computers can potentially accomplish this task swiftly due to their ability to work with qubits.

Classical computers use bits that can be in one state at a time (0 or 1). By contrast, qubits—quantum bits—can exist in superpositions, representing arbitrary combinations of 0 and 1. For instance, two qubits can simultaneously represent four possible states (00, 01, 10, 11), allowing parallel computation of calculations.

However, the results obtained from a quantum computation are embedded in a superposition, and extracting the desired information requires converting the superposition into a state containing only the relevant data—a challenging process.

Quantum computers have an advantage over classical computers when it comes to factoring large numbers, thanks to an algorithm called Shor's algorithm, developed by Peter Shor and Don Coppersmith in 1994. Shor's algorithm employs the quantum Fourier transform to extract frequency information from periodic superpositions, enabling the determination of the exponent required to reach one more than a multiple of a given number.

This exponent can be used to find the prime factors of a product, and thus break the encryption. While classical computers struggle with factoring large numbers efficiently, quantum computers can potentially perform these calculations at a much faster rate.

To exploit Shor's algorithm and factorize the product of two primes, a quantum computer requires a significant number of qubits. The number of qubits needed has been decreasing over time, but it still surpasses the capabilities of current quantum computers. Estimates suggest that breaking RSA encryption would require billions of physical qubits.

However, progress is being made in quantum computing, and the number of qubits is expected to grow exponentially. It's a matter of time before quantum computers reach the point where they can break existing public key encryption methods.

In anticipation of this threat, researchers have been working on developing new encryption algorithms that are resistant to attacks from both classical and quantum computers. In 2022, the National Institute of Standards and Technology (NIST) selected four post-quantum cryptographic algorithms from 82 proposals submitted by cryptographers worldwide.

Three of these algorithms are based on lattice mathematics, which involve using sets of vectors to construct lattices that are difficult to work with. By sharing the lattice publicly while keeping the specific vectors secret, encrypted messages can be sent, and only the intended recipient, who possesses the appropriate vectors, can accurately decipher the message. The complexity of solving the closest vector problem in high-dimensional lattices makes these algorithms resistant to both classical and quantum attacks.

As the development of quantum computers and advancements in encryption continue, experts and cryptographers play a crucial role in ensuring the security of sensitive data, protecting critical infrastructure, and countering mass surveillance.

It is essential to stay informed about the evolving landscape of quantum computing and encryption methods to maintain data security.