This application provides a communication method and apparatus. The method includes: A terminal device receives indication information from a master node, where the indication information indicates that a key used for signaling transmission performed between the terminal device and a first secondary node by using a second SRB is a first key, the first key is a key used for signaling transmission performed between the terminal device and the master node by using a first SRB, and the first secondary node and the master node share one CU. In a scenario in which the master node and a secondary node share one CU, the terminal device determines that a key for signaling transmission performed between the terminal device and the secondary node is the same as a key for signaling transmission performed between the terminal device and the master node, which avoids complexity.