With the rise of smart cities, Cooperative intelligent Transportation Systems (C-ITS) became one of the main use case scenarios. Within these environments, Public Key Infrastructures (PKI) represent the major solution to ensure the needed security requirements. Knowing that communications between the PKI and the vehicle stations or the Road Side Unit stations must be secure, the traditional way to request certificates is too costly in terms of execution time, computation and amount of exchanged data on the network. Besides, it exists a new scheme to request certificates called butterfly keys, which was designed in a way to optimize certificates request process. However it was also designed to fit SCMS project architecture. In this work we adapt butterfly keys scheme to traditional PKI architectures. Then, we implement both of certificate requests schemes and provide a deep performance comparison. This performance comparison shows clearly the efficiency of the butterfly keys scheme over the other one.