Cambridge, United Kingdom, 5th March 2025: Toshiba Europe Limited has today announced that its commercially available quantum key distribution (QKD) systems now natively incorporate the latest post quantum cryptography (PQC) standard, bringing an additional layer of security to its quantum-safe networking platform.

Our connected society relies on the encryption of our private data to maintain its secrecy. Today’s security relies on ‘one-way’ mathematical functions, which are easy to calculate in one direction, but are almost impossible in reverse, even using the most powerful supercomputers.

However, as a quantum computer will be able to solve efficiently all the one-way problems commonly used in cryptography today, there is a pressing need to develop new cryptographic methods that are secure from quantum attacks. Recognising this need, in 2024, the EU published a recommendation calling for co-operation in developing quantum-safe networks.

QKD and PQC are the two main methods that have been developed to protect against future quantum-based attacks.

QKD is a hardware-based method that uses particles of light to distribute secure encryption keys across optical networks. The protocols used for QKD can be proven to be secure from all computational attacks, including both those using a quantum computer, and those which have yet to be discovered. Developed and commercialised over two decades, QKD has already been deployed in networks globally.

In contrast, PQC more closely resembles the cryptography used today in that it is also based on algorithms, but uses new one-way functions, for which no attack with a quantum computer is known today. Following stringent testing, the US-based National Institute for Standards and Technology (NIST) released standards defining the first set of PQC algorithms in 2024, which have now been incorporated into the Toshiba quantum-safe platform.

Combining QKD and PQC for defence in depth

QKD and PQC each have respective benefits and trade-offs in terms of hardware-based absolute security and software-based scalability. A combination of PQC and QKD can utilise the benefits of both methods, providing crypto-agility and ensuring ‘defence in depth’ for users.

Toshiba’s new capability means that its commercial QKD systems can now natively use the current NIST PQC Key Encapsulation Mechanism (ML-KEM) standard. QKD keys can be combined with PQC keys and conventional Diffie Hellman keys, if required.

This capability is provided as an option on new Toshiba QKD systems and available as a software upgrade to already deployed systems. In addition to this, new PQC algorithms released by NIST in the future can be easily added to the Toshiba quantum-safe platform.

This makes it easier for organisations to simultaneously deploy both QKD and PQC to better protect their networks from quantum-based attacks.

“Organisations need to take action now to protect their communications against quantum computing-based attacks, and this enhancement to our QKD systems makes doing so much easier,” said Andrew Shields, Head of the Toshiba Quantum Technology Division. “Natively supporting the deployment of PQC algorithms within our QKD systems is a huge step forwards in giving our customers the flexibility and agility to adopt the right quantum-safe strategy for their organisation, while also allowing for further futureproofing as quantum threats evolve.”