Wireless reprogramming for a wireless sensor network is the process of uploading new code or changing the functionality of existing code. For security reasons, every code update must be authenticated to prevent an adversary from installing malicious code in the network. All existing reprogramming protocols are based on the centralized approach in which only the base station has the authority to initiate reprogramming. However, it is desirable and sometimes necessary for multiple authorized network users to simultaneously and directly reprogram sensor nodes without involving the base station, which is referred to as distributed reprogramming.