The BB84 Quantum Key Exchange Protocol Explained

#cryptology, #cryptography, #cryptanalysis

The BB84 is a key exchange protocol for establishing a secret key between two parties (e.g. Alice and Bob) securely. In contrast to other (common) protocols like Diffie-Hellman-Merkle or RSA, the BB84 protocol's security is not based on hard mathematical problems. Its security is based on actual physical properties of light (quantums). Due to that, Alice and Bob exchange a key using light and they can measure if an attacker (Eve) is also listening and receiving the key while they exchange it. If they detect and attacker, they change their communication channel and restart the protocol.

In this video, we explain how the BB84 protocol works. We also have a look at its security, so what happens when an attacker is present. Finally, we have a look at the implementation of a simulation of the BB84 protocol in CrypTool 2.

If you are interested in learning the basics of cryptology, you should also have a look at our video series about basics of cryptology – also for beginners:    • Basics of Cryptology – Part 1 (Crypto...  

You may download the latest version of CrypTool 2 from here: https://www.cryptool.org/en/ct2/downl...