By analyzing this information, the attacker can determine with whom the human rights organization corresponds, as well as when the correspondence occurred, and what quantity of information was exchanged. Human rights organizations use anonymity to defeat traffic analysis. At the simplest, and least safe, level the sender might use a pseudonym. The attacker does not need to be able to access the messages' contents. Instead he needs only to study the sending and receiving information stored in the message headers.
Traffic analysis can betray devastating information about a human rights group.
For example, if a law firm is offering legal assistance to ensure due process for people accused of nonviolent political crimes, or seeking redress for people tortured in detention, traffic analysis might show that the law firm's email account is frequently corresponding with Human Rights Watch in New York or Washington, or with Amnesty International in London. The mere fact that a given account has frequent correspondence with one of these two internationally-known organizations is sufficient for an attacker to know that the group is engaged in human rights work. This group could then be defamed as a pawn of the West, or subject to more direct repression. Traffic analysis might be more subtle. For example, if a group in China sends electronic mail to Amnesty International, and Amnesty issues an urgent action relevant to a person known by one of the account's users a day or two later, someone watching the Chinese group's account and Amnesty International's actions might reasonably conclude that the message from the group to Amnesty had been the source of information for the urgent action.