Mini-satellite paves the way for quantum messaging anywhere on Earth
16 comments
·May 19, 2025ortusdux
staunton
"QKD is already used by banks and governments to transmit keys over fibre optics."
I wonder what specific uses they mean. It's kind of hard to believe those are "serious" use-cases, going beyond demonstrations done for marketing reasons... Then again, as soon as you have a serious use-case, you don't tell anyone about it, so it's really hard to evaluate how much (if at all) this stuff is really used in practice.
rhdjsjebshjffn
Quantum key distribution is a real thing. It's a very specific set of constraints that would make it generally attractive, though, namely not relying on networks of trust to function, maybe? Key distribution as a dumb pipe.
0_____0
Yes, hollow-core fibers also attenuate light.
AnonC
Can someone else who’s more of an expert or well read in the area explain the following to me? I thought quantum computing requires very low temperatures and highly controlled environments, and that’s why it’s not commonly available (cost is, of course, another huge barrier). In this case, does the satellite conform to those requirements or is it something else? Do both the sending and receiving systems conform to those physical requirements? Can this system be deployed almost anywhere on earth at a low cost?
Other than money, what are the non-negotiable requirements for such a system to be deployed and to work as expected? What is the exact breakthrough here?
bawolff
This is about quantum messaging not quantum computers. They don't have the same requirements.
However its pretty useless. QKD, does basically the same thing as the diffie-helman protocol, except with less math assumptions. Like diffie-helman it protects against passive evesdroppers but not active man in the middle. Any real system is going to have to use traditional crypto for active MITM protection, and if you are already using traditional crypto, might as well use it for the whole thing.
In essence this is a cool science experiment but doesn't really offer meaningful improvements over traditional crypto methods.
noqc
Key distribution is already solved until someone can actually solve a large discrete logarithm problem with a quantum computer.
You cannot use this mechanism to send messages, only to agree on a secret that neither party chooses.
dzonga
this is impressive stuff -- I wonder for military applications how it will change military logistics ?
ck2
one thing is for sure, the next world-war they are just going to take out every satellite in the first 5 minutes
the micro-debris will make orbits impossible for the next century
and that's assuming they don't use EMP from orbit to take out ground communications too like starfish prime
RajT88
That is a better case scenario than immediate nuclear annihilation.
ck2
I think there is a dangerous misunderstanding that the population of earth could survive even a small number of nukes being used anywhere on the planet
It would be a slow-moving but certain mass-extinction event
A single modern nuke is 30-80 times more powerful than Hiroshima
And then look at the socio-economic devastation of something like Covid
null
nancyminusone
Go look at the Nevada Test Site on Google maps. About 1000 nukes were set off there. Las Vegas is only about 100 miles away and by all accounts seems to be thriving.
In a nuclear attack, it's unlikely "we'll" be fine, but someone will be.
lupusreal
That's nothing new really, late cold war wargames have satellites like the RORSATs playing a big role, and that's when anti-satellite weapon development really became a thing.
Low LEO will mostly clear out in a few years. And for really important satellites that matter a lot no matter what the cost, they can still be used. You just have to accept a higher rate of attrition.
"QKD is already used by banks and governments to transmit keys over fibre optics. But these cables absorb photons, limiting the distance over which the signal can travel."
Does hollow-core fibre suffer the same limitation?