A short overview of an alternative software solution for everyone interested in the German Eichrecht and the future of e-mobility (roaming) protocols. Presented at the S.A.F.E Initiative meeting on 19. Dec 2018 in Berlin.

1. Chargy
E-Mobility Transparency Software
Best read during listening to the Danish National Symphony Orchestra: https://www.youtube.com/watch?v=k6zCLs1_LnI
v0.8 “Return of the Jedi”

2. Current Situation
EVSE, Authorization,
Timestamps, Meter Values, …
e-Mobility
Provider
As found in OICP, OCHP, OCPI, eMIP, OIOI, …
Best read during listening to the Danish National Symphony Orchestra: https://www.youtube.com/watch?v=enuOArEfqGo
Charging
Station
Energy
Meter
Charge Detail Record Charge Detail Record
Charging
Station
Operator

3. Problems
• German “Eichrecht” requires more security, accountability,
tamper protection, … for Charge Detail Records (CDRs)
• In todays e-mobility market CDRs are often too late and/or
incorrect. Far too many complains.
• Todays roaming protocols do not provide any kind of
workflows or solutions for these issues

4. Session Information
Location Information
Tariff Information
Crypto Algorithms, Public Keys
Offline Transparency
e-Mobility
Provider
The PTB “Günstige Lösung” Usecase
Best read during listening to the Danish National Symphony Orchestra: https://www.youtube.com/watch?v=enuOArEfqGo
MeterId, Authorization, Timestamped & Signed Meter Values
Signed Meter Values Charge Transparency Record (CTR)
Charging
Station .
Operator
Charging
Station
Smart
Meter
Crypto
Signature
Crypto
Signature

5. Session Information,
MeterId, Authorization, Timestamped & Signed Meter Values
Location Information
Tariff Information
Crypto Algorithms, Public Keys
Offline Transparency
e-Mobility
Provider
The alternative ChargePoint Inc. approach
Best read during listening to the Danish National Symphony Orchestra: https://www.youtube.com/watch?v=enuOArEfqGo
Charge Transparency Record (CTR) .
Charging
Station
Energy
Meter
Note: Every information must be sent to, calculated and signed within the charging station!
This is especially important for any roaming use case.
Can you trust all your charging stations? Securing physical access is very hard.
Charging
Station
Operator
Crypto
Signature

6. Challenges
1. PTB use case is far far away from the EV drivers’ use case
and modern software development!
2. How to receive a verified public key of a smart meter?
3. How to receive the CSO/EMP tariff for a charging process?
4. How to secure the entire CTR from manipulation?
5. How to receive additional verified public keys of charging
stations, CSOs, EMPs?

7. Approach
• Extend core ideas of ISO/IEC 15118 to German “Eichrecht”
• Remove business model limitations and legacy crypto
• Reuse 15118 private/public keys; add domain-specific
certificates for e-mobility
• Solve security & privacy violations of 15118/OCPP/OCPI/…
• Replace 15118 wire-protocol by more modern approaches
• Adapt OCPP/OCPI/… to German “Eichrecht”

8. Our User Groups
• German Physikalisch-Technische Bundesanstalt (PTB)
• Every Electric Vehicle Driver
• CPOs for accounting, verification and automated tests
• EMPs for accounting, verification and automated tests
• Navigation Providers, eCar OEMs, Energy/Grid companies, Smart Cities…
(in the future)

9. Digital Identities
Everyone has at least one Public Key/Digital Identity
• Smart Meters to sign esp. energy meter values
• Station Operators to sign esp. tariffs and entire CTRs
• E-Mobility Providers to sign final invoices
• Stations to sign any data transmission
• EV Drivers to sign Remote Starts/-Stops via EMP-signed One-Time-Keys

10. Certificate
MeterId: #2305/1
Public Key: 0x0359350…
Allowed Ops: Sign Meter Values
Issuer: GraphDefined CSO
Smart Meter
#2305/1
Charging
Station #2305
EV Driver
#420005
Sign/certify Public Key(s) == Trust
Sign/certify Public Key(s) == Trust
Trusted CTRs
GraphDefined
CSO
GraphDefined
GmbH
Decentralized Trustvia domain-specific cryptographic certificates
Not X.509 certificates like in ISO/IEC 15118, as X.509 means centralization
Digital Identity
ACME EMP
ACME Int.Digital Identity

11. Charge Transparency Data Format
1. OCMF is far from being state-of-the-art
2. Our solution: JSON with some Linked Data ideas
{
"@context": "https://open.charging.cloud/contexts/CTR/unverified+json",
"session": {
"@id": "2ab541f0-74e0-4e01-93b6-90d7845d3cb8",
"begin": "2018-11-04T22:47:03Z",
"end": "2018-11-05T06:29:10Z",
"authorization": {
"@id": "8011E582833804“,
[…]
}
},
[…]

12. Charge Transparency Data Format
3. Might include tariff information
4. Might include pool/station/EVSE (location) information
[…]
"tariff": { … },
"chargingStationOperator": {
"publicKeys": [ {
"algorithm": "secp192r1",
"format": "DER",
"value": "042313b9e469612b4ca06981bfdec…",
"signatures": [ … ]
} ]
},
"chargingStation": { … }, // might be encrypted (GDPR)
"EVSE": { … }, // might be encrypted (GDPR)
"EV": { … }, // might be encrypted (GDPR)
[…]

13. Charge Transparency Data Format
5. Allows 1..n energy meters; inside EVSE, EV, grid, …
6. Allows more than 1 public key; simplified key migration
[…]
"meters": [ {
"@id": "00000001",
"type": "Virtual Meter v1.0",
"location": "EVSE",
"publicKeys": [ {
"algorithm": "secp192r1",
"format": "DER",
"value": "049a88ac54fb4fc8f9d1d5bc5707b…",
"signatures": […]
},
[…]

14. 7. Allows >1 measurement per meter for smart charging
8. Signed meter values are linked via crypto hashes
[…]
"measurements": [ {
"name": "ENERGY_TOTAL",
"obis": "0100011100FF",
"unit": "WATT_HOUR",
"scale": 1,
"values": [ {
"timestamp": "2018-11-04T16:47:00Z",
"value": "1200",
"prevSignatures": […],
"signatures": […]
} ]
} ],
[…]
Charge Transparency Data Format

15. Chargy Desktop App
Electron Framework for Windows, Mac OS X, Linux
OEM-version with branding currently in PTB certification. ETA Jan 2018

16. Chargy Mobile App
Cordova Framework for iOS, Android, Windows Mobile
ETA Q1/2018

17. Additional Challenges
1. Online Transparency
2. Reuse ideas to replace todays RFID/eMAId authentication
3. GDPR/ePrivacy compliant e-mobility protocols
4. Automated complaint management, when transparency
verification failed, or other issues occur
5. Make use of the energy meter within the electric vehicle.
Correlate both meters to detect anomalies.

18. Session Information
Crypto Parameters (Algorithms, Public Keys)
Location and Tariff Information
Session Started
Online TransparencyThe EV-Drivers’ Usecase
Previous Crypto Hash Value
Session Finished
Tariff and Smart Charging Updates
Previous Crypto Hash Value
Meter Value Updates
Charging
Station
Operator
Charging
Station
Smart
Meter
Crypto
Signature
e-Mobility
Provider
Signed & Timestamped Meter Value(s), Pagination
Crypto
Signature
Final Signed Meter Value(s), Pagination
Crypto
Signature
Crypto
Signature
Crypto
Signature
1st Signed & Timestamped Meter Value, Authorization
Crypto
Signature

19. Certificate
Public Key: 0x0165370…
Allowed Ops: Remote Start (22 kW AC)
Issuer: ACME EMP
Charging
Station #2305
EV Driver
#4200054. Remote Start via One-Time Certificate
Sign/certify Public Key(s) == Trust
GraphDefined
CSO
GraphDefined
GmbH
Secure Authorizationvia domain-specific crypto certificates. No more unsecure RFID UIDs!
Not X.509 certificates like in ISO/IEC 15118, as X.509 means centralization
Digital Identity ACME Int.
2. Certificate Signing Request
for 5 public keys
3. Signed for an anonymous EV driver
ACME EMP
1. Sign/certify Public Key(s) == Trust
Digital Identity