The invention discloses a CDMA port-to-port
encryption communication
system and a
key distribution method thereof, the CDMA port-to-port
encryption communication
system comprises a CDMA network and a terminal mobile telephone thereof, a public switched
telephone network and a terminal fixed-line telephone thereof, a
short message service center as well as the following three
cipher processing units including a
cipher chip of a mobile
telephone terminal, a
key distribution management center (KDMC) and a
Firmware cipher module of a gateway mobile switching center. The
key distribution management center is used for key distribution management of the communication
system. The key distribution is realized by a layered
distribution method, i.e. a first layer is an equipment key which is distributed in the process of initialization; a second layer is a key-
encryption key and a
short message service key which are distributed in startup of an enciphered mobile telephone; and a third layer is a
session key which is distributed every time a session is launched between the enciphered mobile telephones. At the same time, by adopting a bidirectional certification technology for key distribution and combination of a key update and remote destroying method, the
safety risk in key
exposure is reduced, and the communication safety is improved.