1. A computer-implemented method for protecting data residing in a repository of an electronic product code information service against undesired data disclosure, the method comprising: defining one or more disclosure policies for an item tagged with an electronic product code, the item having associated data stored in the repository, the one or more disclosure policies describing one or more of: who is permitted to query the repository for information, what type of information is permitted to be obtained from the repository in response to a query, and under what condition the repository can be queried; and enforcing the one or more disclosure policies in response to a received query from a party by only disclosing a subset of the data from the repository, the subset being determined in accordance with the defined one or more disclosure policies.