Algorithm 1 Register Device

Input:  Security parameter $\lambda$, Device ID i, Total budget ${\epsilon }_{tot}$, Limit k, Public Parameters $PP$ Output:  Public keys $p{k}_i,p{k}_i^{vrf}$, Initial state ${\epsilon }_0,re{c}_0$ 1:$(p{k}_i,s{k}_i)\leftarrow \mathrm{Sign}.\mathrm{KeyGen}\left(1^{\lambda }\right)$ 2:$(p{k}_i^{vrf},s{k}_i^{vrf})\leftarrow \mathrm{VRF}.\mathrm{KeyGen}\left(1^{\lambda }\right)$            ▹ Generate independent VRF keys 3:${\epsilon }_0\leftarrow {\epsilon }_{tot}$ 4:$re{c}_0\leftarrow 0^{256}$                       ▹ Initialize receipt chain 5:Store $(s{k}_i,s{k}_i^{vrf})$ using secure mechanism 6:Publish $(i,p{k}_i,p{k}_i^{vrf},{\epsilon }_{tot},k,re{c}_0)$ 7:return $p{k}_i,p{k}_i^{vrf},{\epsilon }_0,re{c}_0$