by Amara Graps

The BB84 protocol

In 1984, Brassard and Bennett presented their 4-page, conference paper,  which described the BB84 algorithm, thus fixing in history the first quantum cryptography protocol for the Quantum Key Distribution (QKD) concept. The BB84 algorithm is still in-use today. See BB84’s roots to physics principles in the first words of their Abstract:

When elementary quantum systems, such as polarized photons, are used to transmit digital information, the uncertainty principle gives rise to novel cryptographic phenomena unachievable with traditional transmission media […]  –Brassard and Bennett

Given that QKD distributes cryptographic keys produced by quantum techniques across terrestrial and satellite-based global communications networks, QKD will undoubtedly play a role in the future Quantum Internet. Indeed, Stephanie Wehner, David Elkouss, and Ronald Hanson, published in 2018, a science review: Quantum internet: A vision for the road ahead with QKD at its trusted nodes.

Trusted nodes, secured by QKD protocols, are also inside GQI’s perspective of the evolution of the Quantum Internet. You can find Global Quantum Intelligence’s far-ranging vision of the deployment of the Quantum Internet in GQI’s Quantum Safe Outlook Report. See the next Figure.

Figure. An illustration of Trusted nodes in GQI’s Quantum Safe Outlook Report. (*)

QKD versus PQC

Recent news about NIST’s selection of post-quantum cryptography (PQC) algorithms, highlights divergent views of “quantum secure” technology: one ruled by physics (QKD) and one by mathematical approaches (PQC). IEEE Spectrum recently interviewed GQI’s Doug Finke, to explain these quantum technology differences. In brief:

Theoretically, people cannot predict that these PQC algorithms won’t be broken at some point. On the other hand, QKD- there are theoretical arguments based on quantum physics that you can’t break a QKD network.  

These different views, feed into a variety of approaches for building the Quantum Internet.

Competing visions for the Quantum Internet

Our Quantum Safe Outlook Report and corresponding Quantum Safe State of Play Presentation available for GQI customers (*), explains the journey to build the Quantum Internet, with the Network-led approaches, the Compute-led approaches, and our vision which is agnostic to both, because these are intermediate steps.

[…] investors, companies and governments are faced with overlapping opportunities across four of the great deep tech sectors: cryptography, quantum, AI and space. It’s a challenge to avoid being locked into any one technology or narrow field of expertise. It’s a challenge to evaluate the trade-off of short-, medium- and long-term revenue opportunities; doubly so when we consider the interplay of economic vs geopolitical factors that will likely influence the development of the wider sector. […] Some are focused on how to deploy quantum safe cryptography to build a quantum resistant Internet. Some are focused on building ‘prepare & measure’ quantum networks using trusted nodes to create quantum-enabled networks. Others envision the true entanglement-based Quantum Internet.  

Figure. An illustration of Trusted nodes in GQI’s Quantum Safe Outlook Report. (*)

QCR’s article: Ingredients for a Killer App illustrates some of the needed quantum devices, quantum networks and quantum protocols in the Quantum Internet journey. Our key question is:

 How important are the intermediate steps are in winning the race to build an entanglement-based end goal?

Back to Physics

If you explore some of the Quantum Internet articles with Connected Papers, you may discover that QKD has direct linkages to Einstein and his 1935 public quantum entanglement discussions with Schroedinger and Bohr. Moreover, you can use the (often-misused) academic citation metrics of today to judge the winner of their 1935 debates: Einstein, Podolsky, and  Rosen (24695 Citations), Schroedinger (5385 Citations),  and Bohr (3265 Citations). Who won? Einstein, of course.  

Figure. An illustration of the 1935 Einstein, Schroedinger, and Bohr debates from some early Quantum Internet articles, looking backward through time, via Connected Papers.

(*) Quantum Safe Outlook Report. Despite the challenges, the transition to quantum-safe cryptography is essential to ensure the security of our digital infrastructure in the future. Organizations that start planning now will be well-positioned to meet this challenge. If you are interested to learn more, please don’t hesitate to contact [email protected].

September 9, 2024