Method and related device for generating group key

A mobility management entity, comprising:

• a first receiving module, configured to receive a group ID, sent by a machine type communication (MTC) device, of a group to which the MTC device belongs, or a service ID of a service supported by the MTC device;
• a first sending module, configured to send the group ID or the service ID to a home subscriber system (HSS) serving the MTC device, so that the HSS generates a group communication root key according to a generated random number and a security key corresponding to the group ID, or so that the HSS generates a service root key according to a generated random number and a security key corresponding to the service ID;
• a second receiving module, configured to receive the group communication root key or the service root key from the HSS;
• and
• a second sending module, configured to send the group ID and the group communication root key to a base station, or send the service ID and the service root key to a base station, so that the base station performs the following actions:
• (1) in a case of receiving the group ID and the group communication root key, generates a group key corresponding to the group ID according to the group communication root key, or in a case of receiving the service ID and the service root key, determines, according to the service ID, the group ID of the group to which the MTC device belongs, generates a group communication root key corresponding to the group ID according to the group ID and the service root key, and generates the group key corresponding to the group ID according to the group communication root key;
• and (2) sends, to the MTC device, a generating parameter used to generate the group key, so that the MTC device generates the group key according to the group key generating parameter and a security key which is saved in the MTC device.

A machine type communication device, comprising:

• a sending module, configured to send, to a mobility management entity (MME), a group ID of a group to which the machine type communication (MTC) device belongs or a service ID of a service supported by the MTC device, so that the MME sends the group ID or the service ID to a subscriber home system (HSS) serving the MTC device, the HSS generates a group communication root key according to a random number and a security key corresponding to the group ID, or generates a service root key according to a random number and a security key corresponding to the service ID, and sends the group communication root key or the service root key to the MME, the MME sends the group ID and the group communication root key to a base station, or the MME sends the service ID and the service root key to a base station, and in a case of receiving the group ID and the group communication root key, the base station generates a group key corresponding to the group ID according to the group communication root key, or in a case of receiving the service ID and the service root key, the base station determines, according to the service ID, the group ID of the group to which the MTC device belongs, generates a group communication root key corresponding to the group ID according to the group ID and the service root key, and generates the group key corresponding to the group ID according to the group communication root key;
• a first receiving module, configured to receive, from the base station, a generating parameter used to generate the group key;
• and
• a generating module, configured to generate the group key according to the group key generating parameter and a security key saved in the MTC device.