78 research outputs found
A multi-candidate electronic voting scheme with unlimited participants
In this paper a new multi-candidate electronic voting scheme is constructed
with unlimited participants. The main idea is to express a ballot to allow
voting for up to k out of the m candidates and unlimited participants. The
purpose of vote is to select more than one winner among candidates. Our
result is complementary to the result by Sun peiyong s scheme, in the sense,
their scheme is not amenable for large-scale electronic voting due to flaw of
ballot structure. In our scheme the vote is split and hidden, and tallying is
made for encoding in decimal base without any trusted third
party, and the result does not rely on any traditional cryptography or
computational intractable assumption. Thus the proposed scheme not only solves
the problem of ballot structure, but also achieves the security including
perfect ballot secrecy, receipt-free, robustness, fairness and
dispute-freeness.Comment: 6 page
ARPA Whitepaper
We propose a secure computation solution for blockchain networks. The
correctness of computation is verifiable even under malicious majority
condition using information-theoretic Message Authentication Code (MAC), and
the privacy is preserved using Secret-Sharing. With state-of-the-art multiparty
computation protocol and a layer2 solution, our privacy-preserving computation
guarantees data security on blockchain, cryptographically, while reducing the
heavy-lifting computation job to a few nodes. This breakthrough has several
implications on the future of decentralized networks. First, secure computation
can be used to support Private Smart Contracts, where consensus is reached
without exposing the information in the public contract. Second, it enables
data to be shared and used in trustless network, without disclosing the raw
data during data-at-use, where data ownership and data usage is safely
separated. Last but not least, computation and verification processes are
separated, which can be perceived as computational sharding, this effectively
makes the transaction processing speed linear to the number of participating
nodes. Our objective is to deploy our secure computation network as an layer2
solution to any blockchain system. Smart Contracts\cite{smartcontract} will be
used as bridge to link the blockchain and computation networks. Additionally,
they will be used as verifier to ensure that outsourced computation is
completed correctly. In order to achieve this, we first develop a general MPC
network with advanced features, such as: 1) Secure Computation, 2) Off-chain
Computation, 3) Verifiable Computation, and 4)Support dApps' needs like
privacy-preserving data exchange
Non-malleable encryption with proofs of plaintext knowledge and applications to voting
Non-malleable asymmetric encryption schemes which prove plaintext knowledge are sufficient for secrecy in some domains. For example, ballot secrecy in voting. In these domains, some applications derive encryption schemes by coupling malleable ciphertexts with proofs of plaintext knowledge, without evidence that the sufficient condition (for secrecy) is satisfied nor an independent security proof (of secrecy). Consequently, it is unknown whether these applications satisfy desirable secrecy properties. In this article, we propose a generic construction for such a coupling and show that our construction produces non-malleable encryption schemes which prove plaintext knowledge. Furthermore, we show how our results can be used to prove ballot secrecy of voting systems. Accordingly, we facilitate the development of applications satisfying their security objectives
Secret, verifiable auctions from elections
Auctions and elections are seemingly
disjoint.
Nevertheless, similar cryptographic primitives are used
in both domains. For instance, mixnets, homomorphic encryption and trapdoor
bit-commitments have been used by state-of-the-art schemes in both domains.
These developments have appeared independently. For example, the adoption of
mixnets in elections preceded a similar adoption in auctions by over two decades.
In this paper, we demonstrate a relation between auctions and elections:
we present a generic construction for auctions from election schemes. Moreover,
we show that the construction guarantees secrecy and verifiability,
assuming the underlying election scheme satisfies analogous security properties.
We demonstrate the applicability of our work by deriving auction schemes from
the Helios family of election schemes.
Our results advance the unification of auctions and elections, thereby facilitating the progression of both domains
Ballot secrecy: Security definition, sufficient conditions, and analysis of Helios
We propose a definition of ballot secrecy as an indistinguishability game in the
computational model of cryptography. Our definition improves upon
earlier definitions to ensure
ballot secrecy is preserved in the presence
of an adversary that controls
ballot collection.
We also propose
a definition
of ballot independence as
an adaptation of an indistinguishability game
for asymmetric
encryption. We prove relations between our definitions. In particular, we prove
ballot independence is sufficient for ballot secrecy in voting systems with
zero-knowledge tallying proofs. Moreover, we prove that building
systems
from non-malleable asymmetric encryption schemes suffices for ballot secrecy,
thereby eliminating
the expense of ballot-secrecy proofs for a class
of encryption-based voting systems. We demonstrate applicability of
our results by analysing the Helios voting system and its mixnet variant.
Our analysis reveals that Helios does not satisfy ballot secrecy in the presence of
an adversary that controls
ballot collection. The
vulnerability cannot be detected by earlier definitions of ballot secrecy, because
they do not consider such adversaries. We adopt non-malleable ballots
as a fix and prove that the fixed system satisfies ballot secrecy
Multiplexing schemes for homomorphic cryptosystems
We present in this article two secure multiplexing and demul- tiplexing schemes that use homomorphic properties from known public key cryptosystems. One scheme is suitable for cryptosystems with addi- tive homomorphic properties such as Paillier and Benaloh cryptosystems. The proposed scheme employs a modiļ¬cation of Hadamard codes to generate a set of orthogonal codes over Z3. The other one is suitable for cryptosystems with multiplicative homomorphic properties such as RSA and ElGamal. Both schemes might be used in voting and auction systems where anonymity of the individuals is crucial
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