If you start the LiveCD only to use online banking there isn't much time between the startup and the time you need randomness for a secret key. The question is if there is enough time to gather sufficient entropy from the environment.

Others have suggested to seed with the current time, but that is easy to guess for an attacker. Netscape's original SSL implementation was broken because the PRNG used only the current time (in microseconds) and the PID as a random seed ([1], [2]).

[1]: http://marc.info/?l=bugtraq&m=87602167418753&w=2
[2]: http://www.cs.berkeley.edu/~daw/papers/ddj-netscape.html

Since a LiveCD doesn't save anything between reboots, it doesn't have a random seed that it keeps changing. Therefore the random number generator is initialized to the same state every time a system is booted (and probably to the same state for all computers using a specific LiveCD image). When the random number generator is in a predictable state, isn't the security of SSL essentially gone? To work around this, one can add some randomness to the random number generator on boot, but it is extra hassle. Something like "echo ssj s lsl sfi random hits on keyboard shdflsh sl fhlinaw nvnai dnsi >/dev/random"

During the "hardware phase" of a quantum key exchange there is a certain amount of noise that has to be corrected due to imperfections in the channel and that means that there is in practice always possible with some information leakage. The apparatus therefore estimates the maximum possible amount of information leakage (making sure it is overestimated rather than underestimated) and performs "privacy amplification" to make sure that this information is useless to an eavesdropper (this lowers the key rate and is one of the reasons it is only 1 kbps). Now say an eavesdropper finds a new source of information leakage. This is only a problem if the total information leakage is greater than the estimated maximum leakage.

I agree that creating and securing these HDDs is much cheaper, but a QKD system would fail more gracefully if you have a security breach in some realistic scenarios. Imagine that in month 2 you had an employee with malicious intent at your secure site. If this employee would be able to copy the 1 TB HDD, anyone outside would be able to decrypt anything during the next 31 years. The same person would only be able to leak information from his period of employment if a continuously generated key is used. (This is a somewhat oversimplified version of an argument made by a MagiQ representative)

QKD probably has a place in niche markets (companies like MagiQ and IdQuantique actually have customers). An intersting observation regardig the cost of QKD devices is that the cost of a full system is not much higher than the single photon detectors they contain. This means that if somebody finds a way to manufacture single photon detectors cheaply, the cost of QKD devices will drop drastically. If the devices are not very expensive and you already have fibers, why not use them?

Disclaimer: I have benefited from SECOQC funding, but have not worked on anything related to the implemented network or any other QKD implementations.

Well, the point of the SECOQC network is to demonstrate a network with routing capabilities. It is a network that consists of many point-to-point links.

Quantum mechanics has been tested over several decades and has been found to describe the world we live in very accurately. Any post-quantum deviations would be very minor. We cannot exclude the possibility that if someone is able to put the fiber through a wormhole, something strange would happen, but from a bright PhD student imagining this possibility to this becoming realistic there is probably a span of several decades.

Also, a quantum cryptography protocol will have to be broken at the time of the key exchange. If someone realizes two minutes later how it could have been broken it's too late. With modern cryptography the encrypted messages may be intercepted and stored until some bright PhD student in computer science makes a breakthrough, so that all messages sent in the past can be decrypted.

Yes, it could if if devices allow for this. This has been known for years and no modern device that lets this happen will be taken seriously.

I thought you there was no copyright on data under US law. C.f. the OpenStreetMap legal issues http://www.opengeodata.org/?p=262. There may be contractual rights in the picture, but only if those were negotiated already.

The title and summary gets this paper all wrong. It does not propose that ocean currents are causing the earth's magnetic field. In proposes that many of the small scale variations of the field is caused by variations in ocean currents. The main field is still produced by the core.

The quantum capacity is defined completely analogous to the classical capacity of the channel; the number of error free qubits you can transfer per signal. Since a quantum channel can also be used to transfer classical information (by measuring the output), it also has a classical capacity. Since quantum information cannot be copied without errors it also has a private (or secret) capacity. All capacities are the number of error free quantum/private/classical bits per signal, optimized over all possible encodings.