🚀 go-pugleaf

In <1992Oct12.184051.1@zodiac.rutgers.edu> leichter@zodiac.rutgers.edu writes:

>The attack against the *cryptosystem*, as opposed to the attack against QM,
>goes like this:  The eavesdropper clones the photons and SAVES them - he
>makes no attempt to measure their polarization states yet.  Later, when Alice
>has revealed to Bob (and the eavesdropper) which "regime" (circular or linear)
>each photon polarization is to be measured in, the eavesdropper can safely go
>back and measure just that state.  QM guarantees that he gets the same answers
>Bob did, when Bob measured those same photons in Alice's "regime".  (On the
>ones where Bob chose the wrong "regime", both the eavesdropper and Bob get
>random answers.)  When Bob now tells Alice which photons he read in the
>"right" regime, the eavesdropper learns which of his measurements to keep,
>too.

Even if you can clone photons with the same polarization (not obvious to
me, but not theoretically impossible), this will change the photon count
statistics Bob will get, which may be detectable.


--
Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea
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