Cryptography
Quantum Cryptography
Also known as: Quantum key distribution, QKD
Definition
Cryptography that uses quantum-mechanical properties — typically of photons — to achieve security guarantees impossible with classical communication alone.
Examples
- BB84-based QKD links between Beijing and Shanghai over the Chinese national quantum backbone.
- Toshiba and ID Quantique commercial QKD systems for inter-data-center key exchange.
Related terms
Post-Quantum Cryptography
Classical cryptographic algorithms designed to remain secure against attacks by both classical and large-scale quantum computers.
Diffie–Hellman Key Exchange
A public-key protocol that lets two parties derive a shared secret over an insecure channel without ever transmitting it, based on the difficulty of the discrete logarithm problem.
ECDH
The elliptic-curve variant of the Diffie–Hellman key-exchange protocol, providing the same shared-secret functionality with smaller keys and faster operations.
Cryptographic Key
A high-entropy secret or public value that parameterizes a cryptographic algorithm to encrypt, decrypt, sign or authenticate data.
TLS (Transport Layer Security)
TLS (Transport Layer Security) — definition coming soon.
Perfect Forward Secrecy
A protocol property ensuring that the compromise of long-term keys does not allow decryption of past session traffic.