Measuring anonymity: The disclosure attack

The disclosure attack to user anonymity in the computer network is analyzed. The effects of disclosure attack against user communications protected by an anonymity technique is measured. Anonymity services are vulnerable to attacks involving repeated observations of the users. Quantifying the number of times an attacker must observe a user's anonymous communication acts to find all the user's communication partners is a useful measure of anonymity. The analysis presented lets anonymity service participants select parameters according to their privacy needs and build a more dynamic and transparent anonymity system.