Abstract: A method is presented for secure communication, the method including generating a signature using a private key, a nonce, and at least one of an identifier and a key component; and transmitting the signature, the nonce, a security parameter, and the at least one of the identifier and the key component, wherein the security parameter associates a user identity with a public key, the public key being associated with the private key.

Abstract: A flow control apparatus includes a flow control signal generation device for generating a DC control signal based on an audio signal and at least one proportional valve. The flow control signal generation device includes an audio receiving module, a filter rectifier module, a microprocessor and a proportional valve control signal generation module. The filter rectifier module generates at least one DC audio signal by filtering the audio signal provided by the audio receiving module. The microprocessor generates a plurality of period attenuated values based on the DC audio signal. The proportional valve control signal generation module filters the audio signal, attenuates the signal based on the period attenuated values, and then performs filtering and rectification processing to generate the DC control signal, such that the proportional valve may control the opening ratio of the proportional valve based on the DC control signal.