Figure 1: Protocol for quantum computing on encrypted data.
From: Continuous-variable quantum computing on encrypted data
The three stages of our protocol: encryption, gates, and decryption, are illustrated for a coherent state input where we include a transmission step in both directions between the client and server. Input: a displaced vacuum state is prepared as indicated by the red box. Encryption: Next, in the green box, a random displacement is applied to the initial state as an encryption procedure. Channel: The state is transmitted, denoted by a right arrow, over a Gaussian lossy channel to the server (transmission t). Gate: The server applies the desired unitary (a Gaussian displacement or squeezing operation in our experiment), indicated by the yellow box. Channel: The state is sent back over the Gaussian lossy channel to the client, shown in the figure as a left arrow. Decryption: The client applies a decryption operation to retrieve the final output state as described in the blue box.
