Another free-rider attack involves attackers using participating computers to broadcast information. For example, a cracker might wish to make his pirated-software collection available to his friends but lacks the bandwidth to do this from his home PC. He can join our system and place the data to be broadcast on each of his partners in the clear; he then gives out his partners' IP addresses via email to his friends, who then download the data from the partners, subjecting them to unfair high traffic.
This attack is easily thwarted, however, by imposing a quota on how many reads or writes a partner can do per day, say three times the number needed for daily backup. A somewhat larger quota may be needed during restorations.