QSO QUANTUM CRYPTOGRAPHY LAB

Quantum Key Distribution (BB84 Protocol) & Eavesdropping Interception

QKD Scenarios:

Photon Speed:

🟢 Live Server Connected

⚡ QUANTUM OPTICAL FIBER (Qubits / Photons) QUANTUM CHANNEL: Ready for Photon Transmission 📡 PUBLIC CLASSICAL CHANNEL (Sifting & Messages)

QUANTUM CHANNEL (Single Photons)

EVE QUANTUM TAP

CLASSICAL PUBLIC CHANNEL (Sifting & Encrypted Messages)

ALICE

Station ALICE

PHOTON EMITTER & SECURE SENDER

● ONLINE

STEP 1 BB84 Quantum Key Distribution

Number of Photons to Emit:

Alice prepares random bits (0 or 1) in random polarization bases (+ or ×).

Alice's Established QKD Key: NO KEY YET

-- NONE --

Run QKD exchange to negotiate a One-Time Pad key.

STEP 2 Send Message Encrypted via QKD Key

Target Recipient:

Message Payload:

🔐 Encryption Mode: One-Time Pad (XOR with QKD Key)

Alice Transmission Log 0 sent

No messages transmitted yet.

EVE

Station EVE

QUANTUM WIRETAP // UNINTENDED OBSERVER

● WIRETAP ACTIVE

SECTION A Quantum Channel Wiretap (Qubit Interception)

Intercept & Measure Photons on Quantum Fiber Intercept-Resend Attack: Eve intercepts each photon, measures it in a basis, and forwards a newly prepared photon.

Eve's Quantum Measurement Basis: ⚠️ Quantum Principle: Because Eve doesn't know Alice's basis in advance, measuring in the wrong basis collapses the quantum state, introducing ∼25% QBER!

Eve's Stolen Measurement Log: 0 captured

-- No quantum tap data --

Eve's measurements will appear here during QKD.

SECTION B Classical Message Interception (Not Addressed to Eve)

Message Intercept Mode:

👁️ Passive Sniffer

Copies passing message addressed to Bob. Message continues.

🛑 Active MitM (Trap & Tamper)

Pauses message in transit. Allows inspecting ciphertext, tampering payload, or dropping!

Eve's Intercepted Messages 0 captured

No messages intercepted yet.

BOB

Station BOB

PHOTON DETECTOR & INTENDED RECIPIENT

● LISTENING

STEP 1 Single-Photon Detectors & QBER Verification

Quantum Bit Error Rate (QBER): 0.0%

11% Max

Bob's Verified QKD Key: NO KEY YET

-- NONE --

Will match Alice's key if no eavesdropping occurred.

STEP 2 Bob's Decrypted Messages Inbox

No messages received yet.

Reply back to Alice with QKD Encryption:

Uses the established QKD key to encrypt the return message.

Below is the full quantum photon transmission record: Alice's bits and bases, Eve's intercept measurements (if tapped), Bob's detector bases, basis sifting results, and QBER error checks.

#	Alice Bit	Alice Basis	Photon State	Eve Basis	Eve Measured	Bob Basis	Bob Measured	Bases Match?	Sifted Key Bit	QBER Error?
No QKD exchange performed yet. Click "Emit Photons & Run QKD Exchange" to generate data.