In quantum cryptographic protocols, participants typically share both a quantum channel and a classical authenticated channel. Authenticated channels ensure that messages come from legitimate senders and have not been tampered with. However, these channels do not inherently protect against the interception or blocking of messages by an adversary. Blocking or delaying messages in the classical channel is considered an active attack.
Many sources, including the first article in quantum key distribution by Bennett and Brassard, mention that the public channel between participants is only susceptible to passive attacks, not active attacks.
My question is: In quantum cryptographic protocols (such as QKD, QSS, and QPC), can an attacker block or delay messages in the public channel without being detected? If so, wouldn't that compromise the security of many well-established protocols such as the BB84?
In quantum cryptographic protocols, particularly in Quantum Key Distribution (QKD) schemes like BB84, two types of channels are used: the quantum channel and the classical channel.
Quantum Channel:
- Used for: Transmitting quantum states (qubits) which carry the raw key material.
- Security: The quantum channel is subject to quantum mechanical principles, such as the no-cloning theorem and the principle of measurement in quantum mechanics, which provide security guarantees. Any eavesdropping on the quantum channel can be detected because it disturbs the quantum states.
Classical Channel:
- Used for: Public discussion between participants (e.g., Alice and Bob) to compare and verify parts of their key, perform error correction, and apply privacy amplification.
- Security: While the classical channel itself does not have intrinsic quantum security properties, the information transmitted over it is typically protected using classical cryptographic methods like authentication and error correction codes. The security of the entire protocol relies on the integrity of this classical communication, which needs to be authenticated to prevent an adversary from tampering with the messages.
Blocking or Delaying Classical Messages:
Mitigation:
- Authentication: To prevent tampering, the classical messages are authenticated. This ensures that any modified or injected messages are detected by the legitimate parties.
- Redundancy and Resilience: Protocols can be designed to be resilient to temporary blocking or delays, ensuring that the key distribution can continue once the normal communication is restored.
- Classical Security Measures: Standard network security measures, such as using secure and reliable communication channels, can be employed to mitigate blocking and delaying attacks.
In summary, while messages in the classical channel of quantum cryptographic protocols can be blocked or delayed, proper use of authentication and robust protocol design help ensure that these issues do not compromise the overall security of the key distribution process.
In quantum cryptographic protocols, the classical channel used for communication between participants is typically assumed to be authenticated, but not necessarily secure. This means that messages transmitted over this channel can bedelayed
No, messages transmitted in the classical channel between participants in quantum cryptographic protocols are not inherently free from being blocked or delayed. The classical channel is still subject to typical network issues such as interference, congestion, and intentional blocking or delays by adversaries.
- Badges
- Science topic
- Similar topics
- Filing