Protocol Table (last 16 bits)
| Alice Bit | Alice Basis | Bob Basis | Bob Result | Match? | Key |
|---|
Shared Key
Alice's Key:
-
Bob's Key:
-
Error Rate Chart
--- No Eve (~0%)
--- With Eve (~25%)
Controls
BB84 Protocol:
1. Alice encodes random bits in random bases (+/x)
2. Bob measures in random bases
3. They publicly compare bases (not values!)
4. Matching bases = shared key bits
5. Sample key bits to check error rate
Security: If Eve measures a qubit, she disturbs it (no-cloning theorem). This introduces ~25% errors in matched bits, detectable by Alice and Bob.
Qubit States
+ basis: |0> = vertical, |1> = horizontal
x basis: |0> = diagonal /, |1> = diagonal \
Detection
Run the protocol to see if eavesdropping is detected...