A method is provided for processing packets in a security module of a node in a real-time tracking system. The security module receives messages via a communication module. Each message contains an identifier associated with a transmitting entity of the message. A respective identifier is associated with a respective buffer. Messages having a same identifier are stored to an associated buffer. At least one message is selected from each buffer. For each buffer, a verification mode is selected for the message selected based on state variables and identifier-level properties of the identifier associated with that buffer. A buffer for message verification is selected based on state variables and identifier-level properties of all identifiers. The message selected is verified utilizing the selected verification mode. The state variables and the identifier-level properties of all identifiers are updated based on a result of the verification of the at least one message.