Unbreakable solution to digital eavesdropping — At least for now, and the foreseeable future
It is astonishing how fast encryption algorithms that were thought to be fail-proof are being cracked open by security experts. The need for better secure communication techniques has never been more obvious than now, especially with the revelations such as NSA’s PRISM and “President’s Surveillance Program” coming to light in recent times. Enter Quantum Key Distribution (QKD) — a less heard of secure communication mechanism that eavesdropping government agencies wouldn’t want you to know.
Before we delve any further into the internals of the QKD mechanism, be informed that there are some limitations for this extremely powerful protocol that we will need to overcome for this technology to become ubiquitous. QKD is based upon a basic phenomenon of quantum mechanics known as quantum entanglement. I’m no physicist so to keep it simple, entangled particles are basically correlated particles that cannot be described independently even when separated by great distances. This interesting phenomenon is leveraged by QKD to share information where the sender holds one of the entangled particle (photon in this case since the communication medium is usually fiber optics) and the receiver gets the other entangled particle. The receiver’s entangled photon acts as the encryption key without which the transmitted information cannot be deciphered. A important security advantage here comes from the fact that entangled particles cannot be observed or measured without the other particle in the pair knowing about it. I’ve added a couple of wiki links at the end of this article if you are interested in learning more about Quantum communication and Quantum mechanics.
Coming back to the topic of limitations I mentioned above, I can think of mainly two of them from my understanding. It is difficult to maintain coherence for the single photon being transmitted to the receiver even over very high quality optical fibers. The other limitation is that if a piece of information has to be broadcasted to a group of authentic recipients , a group of entangled particles equal in number to the number of recipients is required which is a very difficult feat to achieve. I was super excited to read https://phys.org/news/2018-04-quantum-physicists-entanglement.html">this article recently on phys.org. Physicists were able to generate entanglement between triplets, quadruplets and quintuplets. This is a very exciting advancement and I think if this can be scaled to practical levels, the limitation with broadcasting to multiple recipients would be solved. The limitation of preserving entanglement coherence is being researched and https://www.scientificamerican.com/article/china-shatters-ldquo-spooky-action-at-a-distance-rdquo-record-preps-for-quantum-internet/">this interesting piece of news provides hope by setting a record entangled photon pair transmission of 1203 kilometers using a satellite named Micius. In the meanwhile, hackers are developing several theories and proof of concepts for cracking quantum communication protocols. Though they are simply theories or proofs for now, this is still something to be wary of.
In conclusion, though this all sounds very theoretical and far from becoming mainstream, there are already several networks leveraging this technology such as the DARPA Quantum network and SwissQuantum. There are also commercial QKD systems available already and I’m very positive I’m going to laugh at myself in a couple of years for trying to explain this technology because it is going to become as obvious as the Internet.