The cap on FTP speed with high-bandwidth lines is usually imposed by round-trip time (i.e. ping time) and window size (a setting inside your TCP/IP client/server), NOT by the line performance.
Those who test by FTPing large files and watching the transfer rate, should understand these limitations (kindly explained to me by J.Spencer Love).
I had a similar problem trying to host a large-bandwidth video clip. It turned out the bandwidth of my 10Mbps line did not saturate at all (in fact, it was utilized at mere 5%). The bottleneck was the internal buffer in client and server software.
This also means you may not need that much bandwidth to push the speed of your FTP/TCP-based tasks to its limit.
"Our precise modeling elucidates the specific requirements for scalable quantum computing. for the first time we have translated the requirements for fault-tolerant quantum computing into the specific requirements for gate voltage control electronics in quantum dots, said professor Mark Eriksson."
Translation for those who could not comprehend it:
"We've figured how to build the darn thing on a silicon chip, layer by layer, and have the blueprints. It kinda works in a simulation. We are now going to make a very simple chip (perhaps few gates) and see how our design works in practice. Sure, there will be kinks, but if our idea turns out to be free from fatal flaws, it gonna rock - eventually."
There are algorithms that check a user-chosen password and reject it if the user entered a dictionary word, a frequently chosen combination or anything easily crackable. At the same time, they allow a huge number of passwords that can be easily remembered while being hard to crack by brute-force attack. Any wisely chosen password will pass the check.
When anybody ignores the fact that 30% to 50% passwords entered by random users are easily guessable, they get what they get. It's a known result. You don't need to run a password cracker on every password file, just make sure there is no check at the password input form and you know the outcome.
What you wrote is correct. It's just that I don't know anybody investigating active damage attacks thoroughly. In the paper, we only pointed out that they are possible.
To give one example, for schemes that involve attenuators in the setup, you can shine light down the fiber that is so bright that it will damage the attenuator, and then eavesdrop very conveniently on the signal that is no longer dimmed to single-photon level.
This sort of loopholes in particular implementations or in particular classes of quantum cryptosystems is probably the hardest thing to implement safeguards against.
Not that running an active damage attack is going to be even remotely easy, but as the history shows the cryptanalysts will go to great lengths sometimes (e.g. cracking Enigma).
It's very difficult to rule out implementation loopholes completely.
Or should I say more optimistically, it's time- and resource-consuming to study the implementation looking for every possible loophole and to ensure no loopholes are introduced by incorrect installation and use.
I'd be really interested in a reference to the research on active damage as a method of eavesdropping. We did study one of these strategies, but our experiment was limited to just interrogating Alice's (or Bob's) equipment, not damaging it. If somebod's doing further study, I'd like to hear about it!
As much as I am glad that quantum crypto research receives exposure in the media, there's nothing new in the article. Free-space cryptography has been demonstrated in few places. The latest one promises a 24km link (not quite yet, Dr. Kurtsiefer?).
One comment: even if you need to cool your detector to cryogenic temperatures, you don't have to have your customer pour liquid nitrogen (or did they say liquid helium?) into the commercial device. This is what compact no-maintenance closed-cycle coolers are for.
Their site is very sluggish now, broken graphics, etc.
Looks like they'll need to optimize it for more traffic, even though they usually don't get much of it. The site is your face. Match its performance to your products, damn.
You hereby grant (Brilliant) the right to access and use the unused... bandwidth... The user acknowledges and authorizes this use without the right of compensation.
There is no such thing as unused bandwidth. When the available bandwidth fills up, it forces your provider a costly upgrade, unless he wants the customers to see their Internet access slow down. The cost of upgrade is passed onto end users.
To me, Flash is dead. I permanently removed the plug-in from all my browsers because it cuts down on extremely annoying animated advertizing that uses Flash (and unlike animated GIFs can't be frozen by the browser Stop button) AND I know of no worthwhile site relying onto Flash.
By disabling Flash, you make more good than bad, unless you love large blinking, running and screaming banners!
Can anyone point me at an ISP that does not have something like "we can terminate your account at our sole discretion, at any time, with no reason given whatsoever" in their standard terms of service?
I think, virtually ISPs include this statement. If that was the case with HiNet and they acted in accordance with their Terms of Service, you can't complain about it, period. If you do complain, please at least make it clear whether ISP violated the contract or not.
Don't make politics where there is only commerce. Or so they said shutting down the Russian TV6 channel...
The plug-in crashes my Netscape soon after it begins to download a demo.
The only demo I got to work beyound the pink rabbit screen was "Clown", and it is terribly slow (less than one frame/update per second). Then it crashed on exit from the demo page.
I run Netscape 4.7 for WinNT 4.0 on 300MHz P3 PC with 1GB RAM.
I can only attest that the system works. I've received maybe a couple of Norwegian spams this year.
Last time it came to my mailbox, my immediate thought was "Norway is a small community, there should be a working way to complain and shut down the business" (I knew nothing of what Eivind said here!). I decided not to complain that time, but my office neighbour immediately recited me the appropriate authority from the phone book...
Oops! I've just deleted the Flash plug-in two days ago, both from my Netscape and IE, being annoyed to death by those obtrusive ads I couldn't freeze by the browser Stop button.
I'm afraid, we are seeing the end of this technology. Once many users disable Flash to get rid of the ads, there will be no incentive for Web designers to use it legitimately.
I cannot remember a single site using Flash that I actually cared about and that was useful to me.
See also: Flash: 99% Bad - Alertbox article by Jakob Nielsen (October2000)
Slashdot Mirror
Those who test by FTPing large files and watching the transfer rate, should understand these limitations (kindly explained to me by J.Spencer Love).
I had a similar problem trying to host a large-bandwidth video clip. It turned out the bandwidth of my 10Mbps line did not saturate at all (in fact, it was utilized at mere 5%). The bottleneck was the internal buffer in client and server software.
This also means you may not need that much bandwidth to push the speed of your FTP/TCP-based tasks to its limit.
Translation for those who could not comprehend it:
"We've figured how to build the darn thing on a silicon chip, layer by layer, and have the blueprints. It kinda works in a simulation. We are now going to make a very simple chip (perhaps few gates) and see how our design works in practice. Sure, there will be kinks, but if our idea turns out to be free from fatal flaws, it gonna rock - eventually."
Here is an informal talk by Samuel Braunstein on the problem of teleporting humans.
These techniques are reviewed, for example, in Cryptography and Network Security: Principles and Practice by William Stallings
When anybody ignores the fact that 30% to 50% passwords entered by random users are easily guessable, they get what they get. It's a known result. You don't need to run a password cracker on every password file, just make sure there is no check at the password input form and you know the outcome.
To give one example, for schemes that involve attenuators in the setup, you can shine light down the fiber that is so bright that it will damage the attenuator, and then eavesdrop very conveniently on the signal that is no longer dimmed to single-photon level.
This sort of loopholes in particular implementations or in particular classes of quantum cryptosystems is probably the hardest thing to implement safeguards against.
Not that running an active damage attack is going to be even remotely easy, but as the history shows the cryptanalysts will go to great lengths sometimes (e.g. cracking Enigma).
It's very difficult to rule out implementation loopholes completely.
Or should I say more optimistically, it's time- and resource-consuming to study the implementation looking for every possible loophole and to ensure no loopholes are introduced by incorrect installation and use.
I'd be really interested in a reference to the research on active damage as a method of eavesdropping. We did study one of these strategies, but our experiment was limited to just interrogating Alice's (or Bob's) equipment, not damaging it. If somebod's doing further study, I'd like to hear about it!
One comment: even if you need to cool your detector to cryogenic temperatures, you don't have to have your customer pour liquid nitrogen (or did they say liquid helium?) into the commercial device. This is what compact no-maintenance closed-cycle coolers are for.
Plug #1: idQuantique
Plug #2: Magiq Technologies
Plug #3: Los Alamos lab (yes there used to be a site there)
Plug #4: Our own research (not commercially-oriented yet)
Quantum cryptography at other places:
Quantum Information at Los Alamos National Laboratory
Yup. "NNSA HQ has requested that LANL review all publicly accessible information".
- No sound
- As soon as somebody needs your PC for anything but gaming, you free it immediately.
This works at my university (NTNU).Looks like they'll need to optimize it for more traffic, even though they usually don't get much of it. The site is your face. Match its performance to your products, damn.
There is no such thing as unused bandwidth. When the available bandwidth fills up, it forces your provider a costly upgrade, unless he wants the customers to see their Internet access slow down. The cost of upgrade is passed onto end users.
This IS a theft.
By disabling Flash, you make more good than bad, unless you love large blinking, running and screaming banners!
Instructions on how to remove Flash plug-in. For testing purposes, yeah :-)
I think, virtually ISPs include this statement. If that was the case with HiNet and they acted in accordance with their Terms of Service, you can't complain about it, period. If you do complain, please at least make it clear whether ISP violated the contract or not.
Don't make politics where there is only commerce. Or so they said shutting down the Russian TV6 channel...
The only demo I got to work beyound the pink rabbit screen was "Clown", and it is terribly slow (less than one frame/update per second). Then it crashed on exit from the demo page.
I run Netscape 4.7 for WinNT 4.0 on 300MHz P3 PC with 1GB RAM.
Don't forget to turn the Smart Update back OFF...
Last time it came to my mailbox, my immediate thought was "Norway is a small community, there should be a working way to complain and shut down the business" (I knew nothing of what Eivind said here!). I decided not to complain that time, but my office neighbour immediately recited me the appropriate authority from the phone book...
Oops! I've just deleted the Flash plug-in two days ago, both from my Netscape and IE, being annoyed to death by those obtrusive ads I couldn't freeze by the browser Stop button. I'm afraid, we are seeing the end of this technology. Once many users disable Flash to get rid of the ads, there will be no incentive for Web designers to use it legitimately. I cannot remember a single site using Flash that I actually cared about and that was useful to me. See also: Flash: 99% Bad - Alertbox article by Jakob Nielsen (October2000)
Abouraddy,A., Saleh,B., Sergienko,A., and Teich,M. Quantum holography (PDF, 169KB, 8pages), Optics Express, 9, 498-505 (2001).
Read the damn thing (if you can :-)), then discuss.