BB84 Protocol of quantum key distribution

[@tamimiemran9705]

I LOVE THIS EXPLANATION ITS SO SIMPLE AND ELEGANT AND YET IT GOES INTO TECHNICAL DETAILS. I HOPE YOU GOT A FULL MARK!

[@DrN007]

If you get a 1 on the diagonal basis, the only adjacent other possibility is also a 1 on the rectilinear basis, unless an arrow pointing downwards to denote a 0 could also be a possibility. So how does it work?!?

[@amihart9269]

I'm not sure what you're confused by. It's best to just think of it in terms of a Bloc Sphere, where Alice either transmits the qubit in a computational basis state (|0> or |1>) or applies some sort of gate like a Hadamard gate to it to transform it into a an equatorial state (|+> or |->). The gates are reversible so if Bob applies the gate, it undoes Alice's gate and he reads the same qubit Alice sent, same as if neither applied the gate, but if one applies the gate and the other doesn't, then the gate was applied but never cancelled out, so when Bob goes to measure it he will be measuring a qubit in an equatorial state and thus there will be a 50% chance of a 0 and a 50% chance of a 1, he will be reading random noise rather than the qubit Alice sent.

[@magneticmonopole]

Thank you, it's a very good introduction.

[@thevardhana2537]

AMAZING CONTENT

[@TheTimeDilater]

very nice explaination !!!

[@cryptoinside8814]

So even if the eavesdropper can access both channels and get the basis filter patterns of receiver, the bits would not match on the receiver side, so receiver would know there’s an eavesdropper 👍

[@untabouret3]

Very good video

[@eswarilekhyajarajapu1808]

I had always ad one doubt how can Bob guess exactly half of them rightfully? Why not more or less than that.? Someone please clarify

[@firasel-jerdy8808]

it was purely coincidental here. 8 bits raw key and 4 bit sifted.

[@firasel-jerdy8808]

Alright no. Not coincidental. Because Alice sends a 4n qubits. Bob has to randomly guess either between the standard basis or the Hadamard one. effectively rendering two sifted keys of 2n for both Alice and Bob. kzbin.info/www/bejne/qmO9mWSYhsyjqqc check this video out Ramona explains everything.

[@reb13262]

Bro at 6:41 started speaking cursive

[@sumanghosh6052]

true

[@viaprenestina3894]

it would be nice to have it in English

[@jonbikaku6133]

Wtf

[@chanibastrasecret6195]

very difficult to understand your ascent

[@williamhome8172]

I used cc button.

[@timmy11801]

very difficult to understand your spelling