Encrypted communication method and system based on internet

The invention discloses an encrypted communication method based on internet. A first client end searches a key carrying user identifications of both client ends; if the key is found out, the communication data are encrypted and transmitted; otherwise, a request message for obtaining the keys of the first client end and a second client end is transmitted to a key server; after receiving a key acquiring request of the first client end or the second client end, the key server transmits the key carrying the user identifications of both client ends to the first client end or the second client end; after receiving the encrypted communication data, the second client end searches the key; if the key is found out, the key is decrypted and received; otherwise, the request message for obtaining the keys of the second client end and the first client end is transmitted to the key server, and the encrypted communication data are discarded. The invention also discloses an encrypted communication system based on internet. Th