The example that this article will use is an enveloped XML signature generated over the contents of an XML document, a sample purchase order.
An is a digital signature with several key properties.
Another example of a useful transform algorithm is the XPath Filter transform, which allows you to specify an XPath expression that selects a subset of nodes to be signed.
The element containing the signer's base64-encoded certificate.
the reason for this is that XPath 2.0 redefines '=' to apply to sequences, which means that the above comparison returns true if there is one match when comparing items from the left-hand sequence with comparing items from the right-hand sequence.
this can be very useful if the list of things you want to compare with is dynamic.
Search for validating rss:
XML signatures are a standard for digital signatures in the XML data format, and they allow you to authenticate and protect the integrity of data in XML and web service transactions.