Methods, apparatuses, and computer-readable storage media for secure end-to-end group messaging among devices using dynamic grouping

An apparatus for executing instructions to perform actions of end-to-end group messaging, the actions comprising:

• storing a first local-group (LG) tree in a memory of a first member of a first local group, the first local group comprising the first member and at least one other member, the first LG tree comprising a plurality of LG nodes, the plurality of LG nodes comprising a LG root node connecting to a plurality of LG leaf nodes, the LG root node associated with a LG group key of the first local group, and each of the first member and the at least one other member associated with a respective one of the LG leaf nodes and having a first path from the corresponding LG leaf node to the LG root node;
• storing, in the memory of the first member, a public-group (PG) tree for a public group, the public group comprising the first local group and at least one other local group, the PG tree comprising a plurality of PG nodes, the plurality of PG nodes comprising a PG root node connecting to a plurality of PG leaf nodes, the PG root node associated with a PG group key of the public group, and each of the first local group and the at least one other local group associated with a respective one of the PG leaf nodes and having a second path from the corresponding PG leaf node to the PG root node;
• and
• establishing communication between the first member and one or more members of the at least one other local group at least by using the PG group key.

A non-transitory computer-readable storage medium comprising computer-executable instructions for end-to-end group messaging, wherein the instructions, when executed, cause a processing structure to perform actions comprising:

• storing a first local-group (LG) tree in a memory of a first member of a first local group, the first local group comprising the first member and at least one other member, the first LG tree comprising a plurality of LG nodes, the plurality of LG nodes comprising a LG root node connecting to a plurality of LG leaf nodes, the LG root node associated with a LG group key of the first local group, and each of the first member and the at least one other member associated with a respective one of the LG leaf nodes and having a first path from the corresponding LG leaf node to the LG root node;
• storing, in the memory of the first member, a public-group (PG) tree for a public group, the public group comprising the first local group and at least one other local group, the PG tree comprising a plurality of PG nodes, the plurality of PG nodes comprising a PG root node connecting to a plurality of PG leaf nodes, the PG root node associated with a PG group key of the public group, and each of the first local group and the at least one other local group associated with a respective one of the PG leaf nodes and having a second path from the corresponding PG leaf node to the PG root node;
• and
• establishing communication between the first member and one or more members of the at least one other local group at least by using the PG group key.