Method and related device for generating group key

A method for generating a group key, comprising:

• obtaining a group ID of a group where a machine type communication MTC device is located;
• obtaining a group communication root key corresponding to the group ID;
• and
• sending the group ID and the group communication root key to a base station, so that the base station generates a group key corresponding to the group ID according to the group communication root key and sends the group key encrypted by using an access stratum key of the MTC device to the MTC device.

A method for generating a group key, comprising:

• receiving, from a base station, a group key encrypted by the base station by using an access stratum key of a machine type communication MTC device, wherein the group key is generated by the base station according to a group communication root key obtained by the base station, and is corresponding to a group ID of a group where the MTC device is located, where the group ID is obtained by the base station;
• or the group key is generated by the base station according to a group communication root key obtained from a mobility management entity MME, and is corresponding to a group ID of a group where the MTC device is located, where the group ID is obtained by the MME;
• and
• obtaining the group key through decryption according to the access stratum key of the MTC device.

A base station, comprising:

• a processor, configured to obtain a group ID of a group where a machine type communication MTC device is located;
• the processor, configured to obtain a group communication root key corresponding to the group ID;
• the processor, configured to generate a group key corresponding to the group ID according to the group communication root key;
• and
• a transmitter configured to send the group key encrypted by using an access stratum key of the MTC device to the MTC device, so that the MTC device obtains the group key through decryption according to the access stratum key of the MTC device.

A machine type communication device, comprising:

• a receiver, configured to receive, from a base station, a group key encrypted by the base station by using an access stratum key of the machine type communication MTC device, wherein the group key is generated by the base station according to a group communication root key obtained by the base station, and is corresponding to a group ID of a group where the MTC device is located, where the group ID is obtained by the base station;
• or the group key is generated by the base station according to a group communication root key obtained from a mobility management entity MME, and is corresponding to a group ID of a group where the MTC device is located, where the group ID is obtained by the MME;
• and
• a processor, configured to obtain the group key through decryption according to the access stratum key of the MTC device.