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Voting schemes that provide receipt-freeness prevent voters from proving their cast vote, and hence thwart vote-buying and coer-cion. We analyze the security of the multi-authority voting protocol of Benaloh and Tuinstra and demonstrate that this protocol is not receipt-free, opposed to what was claimed in the paper and was believed before. Furthermore, we(More)
We consider veriiable secret sharing (VSS) and multiparty computation (MPC) in the secure-channels model, where a broadcast channel is given and a non-zero error probability is allowed. In this model Rabin and Ben-Or proposed VSS and MPC protocols secure against an adversary that can corrupt any minority of the players. In this paper, we rst observe that a(More)
Secure multi-party computation (MPC) allows a set of n players to securely compute an agreed function of their inputs, even when up to t players are under the control of an adversary. Known asyn-chronous MPC protocols require communication of at least Ω(n 3) (with cryptographic security), respectively Ω(n 4) (with information-theoretic security, but with(More)
The classical results in unconditional multi-party computation among a set of n players state that less than n/2 passive or Iess than n/3 active adversaries can be tolerated; assuming a broadcast channel the threshold for active adversaries is ta/2. Strictly generalizing these results we specify the set of potential y misbehaving players as an arbitrary set(More)
The goal of secure multiparty computation is to transform a given protocol involving a trusted party into a protocol without need for the trusted party, by simulating the party among the players. Indeed, by the same means, one can simulate an arbitrary player in any given protocol. We formally define what it means to simulate a player by a multiparty(More)
We present a very efficient multi-party computation protocol unconditionally secure against an active adversary. The security is maximal, i.e., active corruption of up to t < n/3 of the n players is tolerated. The communication complexity for securely evaluating a circuit with m multiplication gates over a finite field is O(mn 2) field elements, including(More)
Secure multi-party computation (MPC) allows a set of n players to securely compute an agreed function of their inputs, even when up to t players are under the control of an (active or passive) adversary. In the information-theoretic model MPC is possible if and only if t < n/2 (where active security with t ≥ n/3 requires a trusted key setup). Known passive(More)
It is well-known that <i>n</i> players, connected only by pairwise secure channels, can achieve Byzantine agreement only if the number <i>t</i> of cheaters satisfies <i>t</i> &lt; <i>n</i>/3, even with respect to computational security. However, for many applications it is sufficient to achieve <i>detectable broadcast.</i> With this primitive, broadcast is(More)