Quantum key distribution ________.

• A. Is a way to deliver enormously long keys to communication partners
• B. Creates a major threat to many traditional cryptographic methods
• C. Both A and B
• D. Neither A nor B

Answer: (A)

Quantum key distribution uses quantum states to establish a shared secret key between parties, with any eavesdropping detectable by the legitimate users. Once a key is established, it can be used for symmetric encryption, and its length can be as long as needed to secure the exchanged data. So QKD is fundamentally a way to deliver long keys to communication partners for secure encryption.

It does not inherently threaten traditional cryptographic methods; it provides a secure method for distributing keys, even in the presence of quantum-capable adversaries. The idea that QKD would itself pose a major threat to existing cryptography isn’t the correct emphasis here.