  Smart grids are intelligent power transmission networks that monitor and
control communication participants and grid nodes to ensure bidirectional flow
of information and power between all nodes. To secure the smart grid, it is
very important to design the key agreement protocol. The pairing-free
certificateless two-party authenticated key agreement protocol has been widely
studied and applied as a basic core protocol to protect the security of the
smart grid. Until now, various protocols have been proposed, and these
protocols are being introduced and operated not only in smart grid, but also in
smart cities, healthcare, and vehicle ad hoc networks. In this paper, we
analyzed the security properties of two recently proposed pairing-free
certificateless two-party authenticated key agreement protocols for Smart grid.
According to our analysis, these two protocols are insecure against basic
impersonation attacks of malicious key-generator centers, man-in-the-middle
attacks of malicious key generator centers, and key offset attacks. We also
found and pointed out some errors in the descriptions of these protocols.
