The objective to start this project is primarily to support the ISO and IEC standardisation process to specify the so called "Vehicle 2 Grid Comunication Interface" (V2G CI) which became the ISO IEC 15118 specification by now. We believe that an open source project serves best the need to evaluate the technology under specification, to verify the specified messages, their functionality and thus to enable a stable specification. With these objectives we hope that the project is of help for the ISO/TC 22/SC 3/JWG 1 in their specification work.
Furthermore, the project provides by now a reference implementation of the communication between battery electric vehicles (BEV) or plug-in hybrid electric vehicles (PHEV) and the Electric Vehicle Supply Equipment (EVSE) following the DIN 70121 and the ISO 15118 standard.
The implementation was made possible by the support of Siemens Corporate Technology.
The main scope of the openV2G project is to provide an open source implementation of the latest draft of the ISO/IEC Vehicle-to-Grid Communication Interface (V2G CI) standard. Based on the openV2G library you are able to exchange the standardised XML-based messages between a Plug-In Electrical Vehicle (PEV) and an Electric Vehicle Supply Equipment (EVSE).
The OpenV2G team has started to work on the upcoming 2nd Edition of ISO 15118 (see SVN code).
This version reflects the ISO/IEC 15118-2 FDIS status and is interoperable with OpenV2G 0.7 (DIN track), meaning that one can generate streams with one and decode with the other or vice-versa.
Further, this version resolves XML signature interoperability issues.
Note: To make use of xmldsig the following defines have to be set in "xmldsigEXIDatatypes.h" (otherwise the code is turned off):
#define DEPLOY_XMLDSIG_CODEC SUPPORT_YES #define DEPLOY_XMLDSIG_CODEC_FRAGMENT SUPPORT_YES and in "v2gEXIDatatypes.h" #define DEPLOY_ISO_CODEC_FRAGMENT SUPPORT_YES
In the recent weeks an ambiguity in the ISO 15118 spec w.r.t. XML Signature has been detected due to the incompatibility between OpenV2G and another implementation.
As it is likely that the XML Signature feature is not yet widely used it should be resolved as soon as possible. To evaluate the most pragmatic way to resolve this issue we would like to know until 31st of January 2015 if you are using the XML Signature feature of OpenV2G so far. If yes we would like to ask you to contact us personally so we can discuss the options to resolve this issue.
The questionable part in the core spec is which schema needs to be used to encode the SignedInfo element (Requirement [V2G2-119]). OpenV2G uses the full V2G schema set while at least one other implementation uses XMLdsig schema only.
Even though the specification is not clear what schema to use for this purpose, the informative annex J states the intent as follows "XML signatures only signs the SignedInfo element. Therefore this element needs to be EXI encoded using the schema-informed fragment grammar based on the XMLdsig schema (Canonicalization)." The proposal is now to follow this line which would require to change the OpenV2G implementation with respect to the schema used. A compromise to resolve this issue is to behave as stated in the annex and implement a fix in the core spec.
As stated before the OpenV2G team is implementing this fix we would like to know "who" is using this OpenV2G feature already and for "whom" this change might cause issues. So please contact us before the 31st of January if you are already using XML Signature of the OpenV2G implementation and are concerned about the proposed fix.