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.