LEM DCBM 400 Series - 7.4. Data Authenticity; 7.4.1. Overview; 7.4.2. Keys Specifics

Page 76/95
21January2021/Version 0
LEM International SA
Chemin des Aulx 8
1228 PLAN-LES-OUATES Switzerland
www.lem.com


In the context of metering, data are signed to ensure their authenticity (authentication and integrity).
Signatures secure the following sets of data:
• /ocmf certied, billable transaction data structure
• /legal LEM proprietary transaction data structure
• /logbook bu󰀨er
A signature cannot be used alone. The following set of inputs is necessary as a whole:
• Content to be veried
• Signature for this content
• Associated public key
Once gathered, data authenticity can be veried with the following solutions:


/ocmf API /legal API /logbook API

Transaction data structure,
in certied, billable, OCMF-
compliant format
Transaction data structure, in
LEM proprietary format
Event logbook

OCMF o󰀩cial transparency
software
LEM DCBM verication software
Table 10: Solutions for signatures verification
Verication solutions are given as examples.
• LEM DCBM verication software is available on LEM website or from LEM support
• OCMF transparency software is available at https://transparenz.software/
!
For /legal to be usable for billing in regards to certication, it shall be re-signed by the charger
controller. That is why /ocmf shall be preferred for external backup.

Two unique public keys coexist in each DCBM, to be used according to the dataset to check.

publicKeyOcmf publicKey

/ocmf
/legal, /logbook

In /status API
On the Meter Unit front face marking
In /status API
In /legal API
On the display (boot, end of transaction, maintenance screens)
Figure 43: Keys specifics for signature checks
publicKeyOcmf is composed of an x RFC5480 header and the publicKey
i