In order to prevent manipulation of a specific portion of XML (Extensible
Markup Language) data, data not to be manipulated is extracted from the
XML data, the extracted data is encoded using a secret key of a public-key
cryptographic system, the encoded data is returned to the XML data, an
"encrypt-privatekey" property is given to a tag of the XML data, and a URL
(Universal Resource Locator) data, serving as a location of reference of a
public key corresponding to the secret key is inserted as the value of the
property. If the encoded data can be decoded using the public key acquired
from the URL data, it is possible to confirm that the decoded data is data
formed by a person having the secret key corresponding to the public key,
and that the decoded contents are not manipulated.
