A mechanism for the purchase of tags for copies of software ensures that
identity of the purchaser of a tag table identifier value included in a
purchased tag is not revealed. A mechanism of Call-Ups from the user
device to a guardian center ensures that each tag table identifier value
appears in only one user device and that the data included in a tag table
and other data stored in the user device for the purpose of protecting
vendor's and owner's rights in software, cannot be modified.