XML Security Library performs signature or encryption by processing
input xml or binary data and a template that specifies a signature or
encryption skeleton: the transforms, algorithms, the key selection
process. A template has the same structure as the desired result but
some of the nodes are empty. XML Security Library gets the key for
signature/encryption from keys managers using the information from
the template, does necessary computations and puts the results in
the template. Signature or encryption context controls the whole
process and stores the required temporary data.