  Many voter-verifiable, coercion-resistant schemes have been proposed, but
even the most carefully designed systems necessarily leak information via the
announced result. In corner cases, this may be problematic. For example, if all
the votes go to one candidate then all vote privacy evaporates. The mere
possibility of candidates getting no or few votes could have implications for
security in practice: if a coercer demands that a voter cast a vote for such an
unpopular candidate, then the voter may feel obliged to obey, even if she is
confident that the voting system satisfies the standard coercion resistance
definitions. With complex ballots, there may also be a danger of "Italian"
style (aka "signature") attacks: the coercer demands the voter cast a ballot
with a specific, identifying pattern. Here we propose an approach to tallying
end-to-end verifiable schemes that avoids revealing all the votes but still
achieves whatever confidence level in the announced result is desired. Now a
coerced voter can claim that the required vote must be amongst those that
remained shrouded. Our approach is based on the well-established notion of
Risk-Limiting Audits, but here applied to the tally rather than to the audit.
We show that this approach counters coercion threats arising in extreme tallies
and "Italian" attacks. We illustrate our approach by applying it to the Selene
scheme, and we extend the approach to Risk-Limiting Verification, where not all
vote trackers are revealed, thereby enhancing the coercion mitigation
properties of Selene.

Cryptography and Security;Computers and Society;Applications