Transmitting/receiving method for secret communication

The invention discloses a transmitting/receiving method of covert communication. The method conceals important information waiting convey into a carrier in computer network environment, and importantinformation is unware. When a transmitter transmits network date, a secret information is random embedded into a check field of network protocol date unit (TCP section or UDP) header, and date field is corrected for ensuring check sum right after the secret information is embedded; a receiver extracts the secret information after receiving network protocol date unit from network. The method has better confidentiality and anti-attack by using check and covert information of protocol date unit, and is safely and reliable. The method is especially suitable for convert communication of important information with less date quantity.