Algorithm 2 Registering a service with the service registry.

Require:

B:   Global state of the blockchain.

P:    Service registry smart contract caller.

$N_{srv}$:   Name of the service. Must be unique among all services of the same device.

$I_{dev}$: ID of the device that provides the service.

$I_{org}$:    ID of the organization to which the device belongs.

$V_{srv}$:    Version number of the service.

$D_{srv}$:   A short summary of the service’s function and usage.

$T_{srv}$: The date and time when the last update is made to the service information.

Ensure:

Service information is saved or updated in the blockchain.

1: if $WRITE\notin$ GetCallerPermissions $\left(P\right)$ then

2:  return error      ▹ Abort if caller is not allowed to update the blockchain

3: end if

4: if $I_{dev}\ne$ GetContractCallerId $\left(P\right)$ then

5:  return error          ▹ Abort if caller impersonates another device

6: end if

7: if $I_{org}\ne$ GetContractCallerOrgId $\left(P\right)$ then

8:  return error         ▹ Abort if caller impersonates another organization

9: end if

10: if GetDevice $(I_{org},I_{dev})=\varnothing$ then

11:  return error               ▹ Abort if device is not registered

12: end if

13: $S_{srv}\leftarrow$ Serialize $(N_{srv},I_{dev},I_{org},V_{srv},D_{srv},T_{srv})$

14: $B[I_{org},I_{dev},N_{srv}]\leftarrow S_{srv}$

15: return $S_{srv}$