Toward Unbreakable Quantum Encryption for Everyone

Hacked recently covered the efforts of the Chinese government to build unbreakable quantum communication networks. According to analysts, quantum communications networks are so expensive that they could have a “recentralizing effect,” enabling states to recover the ground that they have lost to decentralizing digital technologies. But what if ultra-secure quantum cryptography could be made available to everyone at low cost?

European researchers at the Institute of Photonic Sciences (ICFO), Institució Catalana de Recerca (ICREA), and other research labs, have developed a fast random number generator based on a quantum mechanical process that could deliver the world’s most secure encryption keys in a package tiny enough to use in a mobile device.

“We’ve managed to put quantum-based technology that has been used in high-profile science experiments into a package that might allow it to be used commercially,” says ICFO researcher Carlos Abellan in a press release of the Optical Society of America (OSA). “This is likely just one example of quantum technologies that will soon be available for use in real commercial products. It is a big step forward as far as integration is concerned.”

The research results are published in OSA’s journal Optica with the title “Quantum entropy source on an InP photonic integrated circuit for random number generation.” The article is open access.

Commercial and Innovative Quantum Encryption Products for Consumers

ICFO QRNG device compared to a € 1 cent coin.
ICFO QRNG device compared to a € 1 cent coin.

The researchers used photonic integrated circuit (PIC) technology to create two quantum number generators integrated into a photonic chip that measures 6 by 2 millimeters in size. The device operates at speeds in the range of gigabits per second, fast enough for real-time encryption of communication data, such as a phone or video calls, or for encrypting large amounts of data traveling to and from a server like that used by a social media platform.

“We have previously shown that the quantum processes taking place exhibit true randomness,” said ICFO and ICREA researcher Valerio Pruneri. “In this new paper, we made a huge technological advance by using a new design that includes two lasers that interfere with each other in a confined space. This makes the device smaller while keeping the same properties that were used in the past experiments.”

Cryptography relies on random strings to generate encryption keys, and the security of encryption techniques depends critically on the quality – true randomness – of the random numbers used as input. Total security is permitted by one-time pad (OTP) encryption, where a plaintext message is combined bit-by-bit with a random key known only to sender and receiver. OTP encryption is mathematically guaranteed to be unbreakable if the key is truly random, used only once, and kept secure.

However, generating high volumes of random numbers fast enough is a challenge. Pseudo-random numbers – apparently random strings generated by an algorithm – are not good enough for high security applications. One needs real random numbers, generated by a physical process that guarantees randomness. Quantum random number generators (QRNGs) exploit the fundamental randomness of the quantum world to produce true random strings, with important applications to secure communications, cryptography, and quantum key distributions.

“We proved that quantum technologies are within practical reach by exploiting PICs,” added Pruneri. “Quantum random number generation as well as quantum cryptography and other quantum-based technologies will benefit from PIC-based technology because it allows one to build commercial and innovative products. Ours is a first demonstration.”

According to the ICFO, the device is the first ultra-fast, true random number generator. The Institute has issued a whitepaper titled “Ultra-Fast Quantum Random Number Generator.” The whitepaper notes that the QRNG technology developed at ICFO was trusted by landmark experiments in fundamental physics. QRNGs have been around for some time, however “they have suffered either from poor speed or measurement bias.”

“Until now…”

The whitepaper states that the ICFO is looking to partner with experts in cryptography, telecommunications and other industries that require ultra-fast and true random number generators.

“Through these partnerships we plan to further develop our technology and maximize its industrial and social impact.”

The fact that the ICFO device “could deliver the world’s most secure encryption keys in a package tiny enough to use in a mobile device” is especially significant. If the ICFO call for partnership is taken by a major (or upstart) phone manufacturer, consumers could soon have ultra-secure personal quantum encryption devices on their phones, which would counterbalance the “recentralizing” effect of large state-owned quantum networks and “redecentralize” communications. A typical use case would be meeting in a secure place and exchange via Bluetooth or NFC a large quantum key to encrypt future secure messages.

Images from ICFO and Shutterstock.

Giulio Prisco is a freelance writer specialized in science, technology, business and future studies.