Quantum Computing

The BB84 Key Exchange Mechanism

The most commonly cited quantum key exchange mechanism is BB84,^[52] named after Charles Bennet and Gilles Brassard, who devised this scheme and presented it at the International Conference on Computers, Systems and Signal Processing in 1984. Over the years, this mechanism has been shown to be highly secure.^{[53] [54]}

In quantum cryptography, both quantum and classical information is exchanged: a quantum channel carries quantum traffic—the mega-qubit— and a classical channel for non-quantum or classical information.

The underlying quantum effect for the BB84 mechanism is based on ​Back-to-Back H Gates: The First Hint of Taming Randomness​. The first H gate takes the qubits and puts them in a blended state. The ...