Secret communication method and system between neighboring user terminals, terminal, switching equipment

A user terminal neighboring to a second user terminal, comprising:

• a determining module configured to determine a neighboring encryption switching equipment between the user terminal and the second user terminal;
• an obtaining module configured to obtain from the neighboring encryption switching equipment an inter-station key for communication with the second user terminal;
• and
• a communicating unit configured to communicate with the second user terminal by using the inter-station key.

An encryption switching equipment neighboring to a first user terminal and a second user terminal, comprising:

• a first receiving module configured to receive an inter-station key requesting packet (M3) transmitted from the first user terminal (STA1) for requesting to help to establish an inter-station key between the first user terminal (STA1) and the second user terminal (STA2);
• a first generating module configured to generate a random number according to the inter-station key requesting packet (M3), take the random number as an inter-station key STAKey1-2 between the first user terminal (STA1) and the second user terminal (STA2), and construct an inter-station key notifying packet (M4), the inter-station key notifying packet (M4) includes identity information of the first user terminal (STA1) and a field of encrypted information of STAKey1-2 protected by a shared key KEYB-2 between the neighboring encryption switching equipment (ESW-B) and the second user terminal (STA2);
• a first transmitting module configured to transmit the inter-station key notifying packet (M4) to the second user terminal (STA2);
• a second receiving module configured to receive an inter-station key notification responding packet (M5) transmitted from the second user terminal (STA2), the inter-station key notification responding packet (M5) includes identity information of the first user terminal (STA1);
• a second generating module configured to construct an inter-station key responding packet (M6), the inter-station key responding packet (M6) includes identity information of the second user terminal (STA2) and a field of encrypted information of STAKey1-2 protected by a shared key KEYB-1 between the neighboring encryption switching equipment (ESW-B) and the first user terminal (STA1);
• and
• a second transmitting module configured to transmit the inter-station key responding packet (M6) to the first user terminal (STA1).