Abstract: Disclosed is a method and apparatus for combatting click fraud. In a system including a first entity, a second entity, a third entity, and a fourth entity, the first entity performs a transaction with the second entity. The transaction between the first entity and the second entity may be an on-line purchase by a client device from an attestor. The second entity causes an integrity-protected classification value to be created. The integrity-protected classification value is derived at least in part from behavioral data about the first entity, and data associated with the classification value is stored in a data repository of the first entity. The first entity then performs a transaction with the third entity, and the transaction causes the stored data to be released to the fourth entity. The fourth entity computes a compensation for the third entity.