Authenticationis the first defence line to prevent malicious entities to accesssmart mobile devices(or SMD). Essentially, there exist many available cryptographic primitives to design authentication protocols.Oblivious transfer() protocol is one of the important cryptographic primitives to design authentication protocols. The first lattice‐based framework under universal composability (UC) model was designed by dual mode encryption and promoted us to find an alternative efficient scheme. We note that “lossy encryption” scheme is an extension of the dual mode encryption and can be used to design UC‐secure protocol, but the investigations of via lossy encryption over the lattice are absent. Hence, in order to obtain an efficient authentication protocol by improving the performance of the UC‐secure protocol, in this paper, we first design a multibit lossy encryption under the decisional learning with errors () assumption and then design a new variant of UC‐secure protocol for authenticated protocol via lossy encryption scheme. Additionally, our protocol is secure against semihonest (static) adversaries in the common reference string (CRS) model and within the UC framework.
Authenticationis the first defence line to prevent malicious entities to accesssmart mobile devices(or SMD). Essentially, there exist many available cryptographic primitives to design authentication protocols.Oblivious transfer() protocol is one of the important cryptographic primitives to design authentication protocols. The first lattice‐based framework under universal composability (UC) model was designed by dual mode encryption and promoted us to find an alternative efficient scheme. We note that “lossy encryption” scheme is an extension of the dual mode encryption and can be used to design UC‐secure protocol, but the investigations of via lossy encryption over the lattice are absent. Hence, in order to obtain an efficient authentication protocol by improving the performance of the UC‐secure protocol, in this paper, we first design a multibit lossy encryption under the decisional learning with errors () assumption and then design a new variant of UC‐secure protocol for authenticated protocol via lossy encryption scheme. Additionally, our protocol is secure against semihonest (static) adversaries in the common reference string (CRS) model and within the UC framework.
Universal composability (UC) is a primary security flavor for designing oblivious transfer (OT) due to its advantage of arbitrary composition. However, the study of UC‐secure OT over lattices is still far behind compared with constructions over prequantum assumptions. Relying on the learning with errors (LWE) assumption, Quach proposes a dual‐mode encryption scheme (SCN’20) for deriving a two‐round OT whose security is provably UC‐secure in the common reference string (CRS) model. Due to its use of a randomized rounding function proposed by Benhamouda et al. (PKC’18), this OT can only be limited to transmitting single‐bit messages. Therefore, conducting trivial repetitions of Quach’s OT when transmitting multibit strings would be very costly. In this work, we put forward a modified dual‐mode encryption cryptosystem under the decisional LWE assumption, from which we can derive a UC‐secure string OT with both full‐fledged dual‐mode security and better efficiency on transmitting strings. The key technique we adopt is a key reconciliation scheme proposed by Jiang et al. (PKC’20), which is utilized to extend the single‐bit symmetric encryption key (produced by the aforementioned rounding function) to a multibit case. Through a comprehensive performance analysis, we demonstrate that our proposal can indeed strike a balance between security and efficiency.
Non-committing encryption achieved only semantic security,in contrast,applications often require security against chosen ciphertext attacks.A main ingredient in the previous adaptive universally composable(UC)oblivious transfer protocols are non-committing encryptions.the previous proposals are not UC secure against adaptive adversaries in the so-called non-erase model.A new UC secure oblivious transfer protocols were proposed and schemes utilize two primitives of the verifiably smooth projective hashing and deniable encryption as constructed by.the double trapdoor decryption mechanism based on trapdoor commitment.Our construction is based on the decisional composite residuosity in common reference string (CRS) model.We constructed a two-message(1-round) string oblivious transfer protocol,which improves computational efficient that supports message spaces of size exponential and save O(n)-1 rounds communications efficient than bit-OT protocols.
Oblivious Transfer (OT) is a fundamental cryptographic protocol that finds a number of applications, in particular, as an essential building block for two-party and multi-party computation. We construct a round-optimal (2 rounds) universally composable (UC) protocol for oblivious transfer secure against active adaptive adversaries from any OW-CPA secure public-key encryption scheme with certain properties in the random oracle model (ROM). In terms of computation, our protocol only requires the generation of a public/secret-key pair, two encryption operations and one decryption operation, apart from a few calls to the random oracle. In~terms of communication, our protocol only requires the transfer of one public-key, two ciphertexts, and three binary strings of roughly the same size as the message. Next, we show how to instantiate our construction under the low noise LPN, McEliece, QC-MDPC, LWE, and CDH assumptions. Our instantiations based on the low noise LPN, McEliece, and QC-MDPC assumptions are the first UC-secure OT protocols based on coding assumptions to achieve: 1) adaptive security, 2) optimal round complexity, 3) low communication and computational complexities. Previous results in this setting only achieved static security and used costly cut-and-choose techniques.Our instantiation based on CDH achieves adaptive security at the small cost of communicating only two more group elements as compared to the gap-DH based Simplest OT protocol of Chou and Orlandi (Latincrypt 15), which only achieves static security in the ROM.
The existing lattice-based cut-and-choose oblivious transfer protocol is constructed based on the learning-with-errors (LWE) problem, which generally has the problem of inefficiency. An efficient cut-and-choose oblivious transfer protocol is proposed based on the difficult module-learning-with-errors (MLWE) problem. Compression and decompression techniques are introduced in the LWE-based dual-mode encryption system to improve it to an MLWE-based dual-mode encryption framework, which is applied to the protocol as an intermediate scheme. Subsequently, the security and efficiency of the protocol are analysed, and the security of the protocol can be reduced to the shortest independent vector problem (SIVP) on the lattice, which is resistant to quantum attacks. Since the whole protocol relies on the polynomial ring of elements to perform operations, the efficiency of polynomial modulo multiplication can be improved by using fast Fourier transform (FFT). Finally, this paper compares the protocol with an LWE-based protocol in terms of computational and communication complexities. The analysis results show that the protocol reduces the computation and communication overheads by at least a factor of n while maintaining the optimal number of communication rounds under malicious adversary attacks.
A new oblivious transfer protocol was proposed within the framework of universally composable security（UC-DT）.The protocol based on the verifiably smooth projective hashing（VSPH） is against adaptive adversaries in a common reference string（CRS） model.The UC-OT protocol improves computational efficiency with non-committing encryptions（NCE）which is based on decisional compounding residuosity,achieves UC-OT,and it saves O（n）-1 rounds in communication efficiency than bit-OT protocols.Compared with Canetti’s scheme in non-erase model,the message reduced once.Compared with Fischlin’s scheme,the message transfers were reduced twice,and the scheme does not rely on the auxiliary party,therefore it is more practical.