22. A method of processing a source document, the method comprising: receiving an XML source document, the source document comprising structural information and content information, the content information comprising a plurality of text tokens; encoding each of the plurality of text tokens individually to produce an encoded XML document; transmitting the encoded XML document to an associated service provider for processing the encoded XML document to generate a modified XML document, without providing the service provider with access to the content information of the XML source document, the encoded XML document being transmitted in a manner which allows the service provider to access at least a part of the structural information without decoding the content information; and generating a transformed document based on the modified document received from the service provider; and outputting the transformed document.
22. A method of processing a source document, the method comprising: receiving an XML source document, the source document comprising structural information and content information, the content information comprising a plurality of text tokens; encoding each of the plurality of text tokens individually to produce an encoded XML document; transmitting the encoded XML document to an associated service provider for processing the encoded XML document to generate a modified XML document, without providing the service provider with access to the content information of the XML source document, the encoded XML document being transmitted in a manner which allows the service provider to access at least a part of the structural information without decoding the content information; and generating a transformed document based on the modified document received from the service provider; and outputting the transformed document. 23. The method of claim 22 , wherein the encoding of the text tokens comprises encrypting each text token with a symmetric private key.