I have protocol required for privacy. Thus, I want to use hybrid cryptography. Base on my knowledge, ECDH is fast and secure. My system consists of 3 main components a trusted-server, client, and server
1- The server will generate ECDH parameters and the private key and compute the public key. These parameters and the public key save at the trusted server. 2- When the client joins the network, the trusted server sends the parameter and public key to the client. 3- The client generates his private key, computes public key and then computes the secret key by using the public key of the server that was received from the trusted server. 4- The client encrypts his message by using the secret key and send the encrypted message and his public key to the server. 5- When the server receives the message, the server computes the secret key by using the public key of the client and decrypts the message by using the secret key.
My questions are: 1- Does this scenario is correct? 2- Can be used ECDH with static public key and parameters?