Abstract: An information exchange method and system, a server and an instant messaging client are provided. The method may include: when receiving a chat session request message sent by a first instant messaging client in an intercom group, receiving, by a server, chat session audio information transmitted by the first instant messaging client; and when receiving a chat session stop message sent by the first instant messaging client, distributing, by the server, the chat session audio information to instant messaging clients, except the first instant messaging client, in the intercom group for real-time playing. The instant messaging client implements an intercom talk function based on a network, thereby saving the purchase cost and improving the confidentiality and stability of information exchange.

Abstract: A method for protecting Register Transfer Level (RTL) Intellectual Property (IP) core is provided, which converts an original RTL IP core to a target RTL IP core embedded with protection measures. The method includes: Step S1, constructing a state machine whose mode is controllable against the original RTL IP core, the state machine has a normal mode appeared corresponding to the normal function of the IP core after the entry of a correct preset secret key value and a fuzzy mode appeared corresponding to the abnormal function of the IP core after the entry of wrong secret key value; Step S2, revise the data flow of the RTL code in the original RTL IP core to obtain the fuzzy RTL code of the IP core; and Step S3: combine the state machine and the fuzzy RTL code into the targeted RTL IP core. By combining the secret key control and fuzzy data flow, the being embezzled and reverse-engineered of RTL IP core can be effectively prevented.