Security and authentication
Work is underway to standardise a mechanism that will allow XML documents to be digitally signed--if you intend to receive purchase orders presented as XML, you'll need a way of checking that they were duly authorised by your client.
But where an e-mail message is typically signed in its entirety, a user or process will want to sign only that portion of an XML document for which it is responsible. For example, a workflow system may require different people to certify the accuracy of data that they entered or that they actually made the decision at their stage of the process.
In a money lending situation, a call centre agent might certify the transcription of the data collected from the applicant while the loans officer would only certify his or her decision to grant or reject the loan.
And where digital signatures are found, encryption is rarely far away: work is in progress to define how data within an XML document can be encrypted. This is clearly important for a variety of applications.
