Key generation can be achieved through online or offline interactive negotiation, such as cryptographic protocols. Key distribution uses a symmetric encryption algorithm for confidential communication, and everyone needs to share the same key.

Communication refers to the exchange and transmission of information between people or between people and nature through certain behaviors or media. In a broad sense, it refers to the communication between two or more parties who need information without violating their respective wishes. Use any method and any medium to accurately and securely transmit information from one party to another.

Exchange information. "Book of Jin·Biography of Wang Cheng": Because he got out of bed, he said: "Why did you communicate with Du Tao?" Li Deyu of the Tang Dynasty wrote "Liu Mian and the Uighur Prime Minister's Letters": He was afraid that the Uighurs would communicate with Tubo, so he ordered soldiers and horses to block the road to Sanhekou. .

Notify the news. Volume 5 of "The Surprise at the First Moment": "Pei Pushe's family decided on a date for the wedding, and asked the matchmaker to come to Zhang Shangshu's house to correspond." Chapter 18 of "Nine Lives of Strange Injustices": "Who doesn't accept the fate of his nephew? "Thank you, who's going to communicate?" Today it refers to using telecommunications equipment or letters to convey information and reflect the situation. The 53rd chapter of Yangu's "Continuing Evil Sea Flowers": "Huafu also asked for a secret code book to be issued for secret communication." Cao Yu's "Beijing People" Act 3: "We can communicate regularly in the future." " People's Daily, December 5, 1982: The freedom of communication and confidentiality of communication of citizens of the People's Republic of China are protected by law.

Articles reporting news. Lu Xun's "Collection of Nanqianbei Diao·Also on the "Third Type of People"": "What I want to say now are just a few points that must be pointed out in the correspondence." Xu Zhucheng's "Baohai Old News" 16: ""Ta Kung Pao" has published rural Survey correspondence, travel correspondence, travel sketching, and battlefield correspondence chaired by Comrade Chang Jiang