Subquantum Crypto Attack
John Young
jya at pipeline.com
Fri Jul 26 09:43:52 PDT 2013
Has subquantum crypto attack been substantiated?
arXiv:quant-ph/0203049v2 12 Apr 2002
Subquantum Information and Computation
Antony Valentini
It is argued that immense physical resources for nonlocal communication,
espionage, and exponentially-fast computation are hidden from us by quantum
noise, and that this noise is not fundamental but merely a property of an
equilibrium state in which the universe happens to be at the present time. It
is suggested that non-quantum or nonequilibrium matter might exist today in
the form of relic particles from the early
universe. We describe how such matter
could be detected and put to practical use. Nonequilibrium matter could be
used to send instantaneous signals, to violate
the uncertainty principle, to distinguish
non-orthogonal quantum states without disturbing them, to eavesdrop
on quantum key distribution, and to outpace quantum computation (solving
NP-complete problems in polynomial time). ...
6 Eavesdropping on Quantum Key Distribution
Alice and Bob want to share a secret sequence of bits that will be used as a
key for cryptography. During distribution of the key between them, they must
be able to detect any eavesdropping by Eve. Three protocols for quantum key
distribution BB84 [20], B92 [21], and E91 (or EPR) [22] are known to be
secure against classical or quantum attacks (that
is, against eavesdropping based
on classical or quantum physics) [23]. But these
protocols are not secure against
a subquantum attack [7]. ...
E91 is particularly interesting for it relies on the completeness of quantum
theory that is, on the assumption that there
are no hidden elements of reality.
Pairs of spin-1/2 particles in the singlet state
are shared by Alice and Bob, who
perform spin measurements along random axes. For coincident axes the same bit
sequence is generated at each wing, by apparently random quantum outcomes.
The eavesdropper cannot elicit any information from the particles while in
transit ..... because there is no information
encoded there [22]. But our Eve has
access to information outside the domain of quantum theory. She can measure
the particle positions while in transit, without
disturbing the wavefunction, and
so predict the outcomes of spin measurements at the two wings (for the publicly
announced axes).12 Thus Eve is able to predict the key shared by Alice and
Bob.
More information about the cypherpunks
mailing list