Bitcoin Forum
December 15, 2017, 08:34:09 AM *
News: Latest stable version of Bitcoin Core: 0.15.1  [Torrent].
 
   Home   Help Search Donate Login Register  
Pages: [1]
  Print  
Author Topic: Question on Quantum Cryptography/Internet  (Read 536 times)
Skrapps
Jr. Member
*
Offline Offline

Activity: 42



View Profile
May 14, 2013, 04:56:22 PM
 #1

From this article: http://www.technologyreview.com/view/514581/government-lab-reveals-quantum-internet-operated-continuously-for-over-two-years/

Quote
...Their approach is to create a quantum network based around a hub and spoke-type network. All messages get routed from any point in the network to another via this central hub.

This is not the first time this kind of approach has been tried. The idea is that messages to the hub rely on the usual level of quantum security. However, once at the hub, they are converted to conventional classical bits and then reconverted into quantum bits to be sent on the second leg of their journey.

So as long as the hub is secure, then the network should also be secure.

The problem with this approach is scalability. As the number of links to the hub increases, it becomes increasingly difficult to handle all the possible connections that can be made between one point in the network and another.Hughes and co say they’ve solved this with their unique approach which equips each node in the network with quantum transmitters–i.e., lasers–but not with photon detectors which are expensive and bulky. Only the hub is capable of receiving a quantum message (although all nodes can send and receiving conventional messages in the normal way).

That may sound limiting but it still allows each node to send a one-time pad to the hub which it then uses to communicate securely over a classical link. The hub can then route this message to another node using another one time pad that it has set up with this second node. So the entire network is secure, provided that the central hub is also secure.

The big advantage of this system is that it makes the technology required at each node extremely simple–essentially little more than a laser. In fact, Los Alamos has already designed and built plug-and-play type modules that are about the size of a box of matches.

I don't understand how this solves scalability. I thought lasers and optics had line-of-sight limitations? Or are they saying from hub to hub is laser, and user to hub is conventional?
Also, at the end of the article they mention quantum routers - How could these route or forward information without disturbing/changing it?

Anybody want to help me out here?
1513326849
Hero Member
*
Offline Offline

Posts: 1513326849

View Profile Personal Message (Offline)

Ignore
1513326849
Reply with quote  #2

1513326849
Report to moderator
1513326849
Hero Member
*
Offline Offline

Posts: 1513326849

View Profile Personal Message (Offline)

Ignore
1513326849
Reply with quote  #2

1513326849
Report to moderator
Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertise here.
1513326849
Hero Member
*
Offline Offline

Posts: 1513326849

View Profile Personal Message (Offline)

Ignore
1513326849
Reply with quote  #2

1513326849
Report to moderator
hashman
Hero Member
*****
Offline Offline

Activity: 915



View Profile
May 14, 2013, 06:39:12 PM
 #2

Modern alchemy.

These guys are pulling the wool over your eyes from time to time so they can stay afloat and hopefully do real important scientific research. 

AzureEngineer
Member
**
Offline Offline

Activity: 98



View Profile
May 14, 2013, 06:45:58 PM
 #3

Quantum internet and quantum computing are two separate utilities. Quantum internet has been around for a few years, its implementation has been slow and expensive. Quantum computing, on the other hand, is not available and most likely will not be available for many decades.

Quantum computing would be big news and it would turn the world upside down. Suddenly all types of internet encryption will be useless, because a quantum computer will not only crack it, but be fast enough to crack it on the fly. If one singular entity has a quantum computer (i.e. the government) then all other non-quantum computers will not be secure.

My name was simply a play on "Blue Engineer" from Team Fortress. I am not affiliated with Microsoft or the Azure project.
Pages: [1]
  Print  
 
Jump to:  

Sponsored by , a Bitcoin-accepting VPN.
Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!