Attacks
Crowds provides perfect anonymity against a corrupt receiver (i.e. see Degree of anonymity) as all members appear equally likely to have been the initiator. As we showed against collaborating corrupt nodes Crowds provides probable innocence as long as (see the paper for the derivation of this), and provides a degree of anonymity . Against the predecessor attack Crowds succumbs in ; this attack works by a corrupt node retaining the previous hop in the path, as this will be the sender more than any other node over the rounds of rebuilding the network it will become apparent who the initiator is. Reiter and Rubin mention this and recommend long (and if possible infinite) time between path reformations (caused when a node in the path leaves the network). Crowds is unable to protect against a global eavesdropper as it cannot use encryption on the links, this is because each node in Crowds is able to communicate with every other node (a fully connected graph), because of this setting up symmetric keys requires pairwise keys; this is too large of a number to be feasible. Against a local eavesdropper again Crowds provides no protection as the eavesdropper will see a message coming out of a node that did not enter, and this positively identifies the node as the sender.
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Famous quotes containing the word attacks:
“We are seeing an increasing level of attacks on the “selfishness” of women. There are allegations that all kinds of social ills, from runaway children to the neglected elderly, are due to the fact that women have left their “rightful” place in the home. Such arguments are simplistic and wrongheaded but women are especially vulnerable to the accusation that if society has problems, it’s because women aren’t nurturing enough.”
—Grace Baruch (20th century)
“Under peaceful conditions, the warlike man attacks himself.”
—Friedrich Nietzsche (1844–1900)
“The rebel, unlike the revolutionary, does not attempt to undermine the social order as a whole. The rebel attacks the tyrant; the revolutionary attacks tyranny. I grant that there are rebels who regard all governments as tyrannical; nonetheless, it is abuses that they condemn, not power itself. Revolutionaries, on the other hand, are convinced that the evil does not lie in the excesses of the constituted order but in order itself. The difference, it seems to me, is considerable.”
—Octavio Paz (b. 1914)