Public Verifiable Threshold Decryption Scheme without Trusted Center

Fault-based side channel cryptanalysis is a very effective cryptanalytic technique against symmetric and asymmetric encryption algorithms. Attackers can induce errors during the encryption or decryption process in order to collect information concerning secret information, such as cryptographic keys. In recent years, the security of the Advanced Encryption Standard (AES) against fault analysis attacks has received considerable attention. While FPGAs are becoming increasingly popular for cryptographic applications, there are only few articles that assess their vulnerability to such attacks only a small number of experiments can be found in the literature on the actual possibility to apply such attacks to FPGAs. The purpose of this paper is to describe a practical and successful implementation of the attack and to provide strong evidence that fault induction is a serious threat against realizations of the AESon FPGAs without effective countermeasure. The results obtained in this paper can serve to design a more secure FPGA implementation of the AES.

Image encryption and decryption using fractional Fourier transform and radial Hilbert transform

In order to guarantee a fair and transparent voting process, electronic voting schemes must be verifiable. Most of the time, however, it is important that elections also be anonymous. The notion of a verifiable shuffle describes how to satisfy both properties at the same time: ballots are submitted to a public bulletin board in encrypted form, verifiably shuffled by several mix servers (thus guaranteeing anonymity), and then verifiably decrypted by an appropriate threshold decryption mechanism. To guarantee transparency, the intermediate shuffles and decryption results, together with proofs of their correctness, are posted on the bulletin board throughout this process.In this paper, we present a verifiable shuffle and threshold decryption scheme in which, for security parameter k, L voters, M mix servers, and N decryption servers, the proof that the end tally corresponds to the original encrypted ballots is only O(k(L + M + N)) bits long. Previous verifiable shuffle constructions had proofs of size O(kLM + kLN), which, for elections with thousands of voters, mix servers, and decryption servers, meant that verifying an election on an ordinary computer in a reasonable amount of time was out of the question.The linchpin of each construction is a controlled-malleable proof (cm- NIZK), which allows each server, in turn, to take a current set of ciphertexts and a proof that the computation done by other servers has proceeded correctly so far. After shuffling or partially decrypting these ciphertexts, the server can also update the proof of correctness, obtaining as a result a cumulative proof that the computation is correct so far. In order to verify the end result, it is therefore sufficient to verify just the proof produced by the last server.KeywordsProof SystemBulletin BoardCommitment SchemeCryptology ePrint ArchiveCommon Reference StringThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

We aim at constructing adaptive oblivious transfer protocols, enjoying fully simulatable security, from various well-known assumptions such as DDH, d-Linear, QR, and DCR. To this end, we present two generic constructions of adaptive OT, one of which utilizes verifiable shuffles together with threshold decryption schemes, while the other uses permutation networks together with what we call loosely-homomorphic key encapsulation schemes. The constructions follow a novel designing approach called “blind permutation”, which completely differs from existing ones. We then show that specific choices of the building blocks lead to concrete adaptive OT protocols with fully simulatable security in the standard model under the targeted assumptions. Our generic methods can be extended to build universally composable (UC) secure OT protocols, with a loss in efficiency.

IoT prevent information leakage to vehicle with the development of the Internet of Things (IoT), it must provide to the second user a vehicle data to keep track of a specific vehicle. In this paper, we propose an access rights approved scheme that used by attribute-based threshold decryption scheme (CP-ABTD) and dynamic threshold cryptography in order to solve this problem.