Quantum Encryption

[JohnWB07]

I have a question on Quantum Encryption. I've been doing a lot of research lately on it and the vendors claim that it is an unbreakable code for key distribution.

 

The basics are that if Alice sends Bob a photon, Bob measures the polarization of that photon which translates into binary. Bob uses a filter to do this. If Bob guesses the right filter to measure the polarization of the photon then in a public conversation Alice will tell Bob that he used the right filter and that photon is translated into a bit.

 

My question is what if Eve uses the same filters as Bob every time a photon was sent? Could she be able to get the key without either Alice or Bob knowing?

 

Thank You

-John