Requesting guidance on EXI fragment encryption and signature

EXI Working Group:

 

Requesting guidance on EXI fragment encryption and signature:

1.      Sometimes want to compress only part of an XML document and
retain the results in context within the new document.

2.      XML signature and XML encryption require XML inputs.

3.      Therefore an EXI document or EXI fragment cannot be signed or
encrypted because they are not XML.

4.      Need formal definition on how to embed an EXI fragment in an XML
document so that it can be signed and or encrypted.

 

Example:

Want to EXI the SequenceOfEvents and retain in the XML document for
digital signature and encryption:

 

<?xml version="1.0" encoding="UTF-8"?>

<PlanOfDay>

    <dayOfWeek date="Monday 18 October 2009"/>

    <Title>Some Tile for the day's Events</Title>

    <SequenceOfEvents>

        <Event>The first event of the day</Event>

        <Event>The second event of the day</Event>

        <Event>The third event of the day</Event>

    </SequenceOfEvents>

</PlanOfDay>

 

....

 

<?xml version="1.0" encoding="UTF-8"?>

<PlanOfDay>

    <dayOfWeek date="Monday 18 October 2009"/>

    <Title>Some Tile for the day's Events</Title>

            EXI of SequenceOfEvents

</PlanOfDay>

 

Could do but:

<?xml version="1.0" encoding="UTF-8"?>

<PlanOfDay>

    <dayOfWeek date="Monday 18 October 2009"/>

    <Title>Some Tile for the day's Events</Title>

    <SequenceOfEvents>

            EXI Fragment of SequenceOfEvents

    </SequenceOfEvents>

</PlanOfDay>

 

However, once the XML is compressed to EXI it is no longer effectively
compressible because EXI will have few if any redundant bytes; no
compression algorithm will deliver good results.  

 

Some potential solutions of consideration:

1.      is a base64 formatting such as Message Transmission Optimization
Mechanism (MTOM)

2.      XML-binary Optimized Packaging (XOP)

3.      Williams, Jeffrey S., Document-Centric XML Encryption and
Authentication for Coalition Messaging, Masters Thesis, Naval
Postgraduate School, Monterey California, September 2009.

 

For additional guidance on the intent of this question please email Don
Brutzman: Brutzman@nps.edu