13 research outputs found
Colonist, 1887-10-14
The Colonist began on 6 March 1886, changing its name to The Newfoundland Colonist after 18 July 1891. Having printed local and international news Monday to Saturday for six years, the paper came to an abrupt end when its offices were destroyed in The Great Fire of 8 July 1892.Title variations recorded in Alternative Title, as needed
New Random Oracle Instantiations from Extremely Lossy Functions
We instantiate two random oracle (RO) transformations using Zhandry\u27s extremely lossy function (ELF) technique (Crypto\u2716).
Firstly, using ELFs and indistinguishabililty obfuscation (iO), we instantiate a modified version of the Fujisaki-Okamoto (FO) transform which upgrades a public-key encryption scheme (PKE) from indistinguishability under chosen plaintext attacks (IND-CPA) to indistinguishability under chosen ciphertext attacks (IND-CCA). We side-step a prior uninstantiability result for FO by Brzuska, Farshim, and Mittelbach (TCC\u2715) by (1) hiding the randomness from the (potentially ill-designed) IND-CPA encryption scheme and (2) embedding an additional secret related to the hash-function into the secret-key of the IND-CCA-secure PKE, an idea brought forward by Murphy, O’Neill, Zaheri (Asiacrypt 2022) who also instantiate a modified FO variant also under ELFs and iO for the class of lossy PKE. Our transformation applies to all PKE which can be inverted given their randomness.
Secondly, we instantiate the hash-then-evaluate paradigm for pseudorandom functions (PRFs), . Our construction replaces by with a key , that, unusually, is known to the distinguishing adversary against . We start by observing that several existing weak PRF candidates are plausibly also secure under such distributions of pseudorandom inputs, generated by . Firstly, analogous cryptanalysis applies and/or an attack with such pseudorandom inputs would imply surprising results such as key agreement from the high-noise version of the Learning Parity with Noise (LPN) assumption. Our simple transformation applies to the entire family of PRF-style functions. Specifically, we obtain results for oblivious PRFs, which are a core building block for password-based authenticated key exchange (PAKE) and private set intersection (PSI) protocols, and we also obtain results for pseudorandom correlation functions (PCF), which are a key tool for silent oblivious transfer (OT) extension
Pseudorandom Correlation Functions for Garbled Circuits
In this paper, we define the notion of pseudorandom correlation generators (PCGs) and functions (PCFs) for garbled circuit correlations.
With a Garbling PCG or PCF, two parties can non-interactively generate a virtually unbounded number of secret-shared garbled circuits and corresponding secret-shared garbled inputs. With the shares of the garbled circuit and garbled input, anyone can recover the garbled circuit and evaluate it to obtain the result of the computation in the clear.
In the process of constructing Garbling PCFs, we introduce a new primitive that we call a Topology-Adaptive PCF (TAPCF), which we construct from two different variants of the learning parity with noise (LPN) assumption. Informally, a TAPCF is a PCF that additionally allows the target correlation to be specified on-demand (i.e., at evaluation time). As a contribution of independent interest, we show that TAPCFs enable the first silent secure computation protocol with function-dependent silent preprocessing. Using our TAPCF construction as a building block, we construct a Garbling PCF that allows the parties to specify the circuit they wish to garble on the fly. Under realistic parameter settings, we estimate that, with our construction, two parties can generate one garbled circuit per second, for circuits with 10,000 AND gates.
Garbling PCFs have several applications: We provide constructions for (1) an efficient homomorphic secret-sharing scheme for specific high-depth circuits, (2) a zero-knowledge proof system over secret shares that supports checking unstructured languages, and (3) a semi-honest reusable two-round, two-party computation protocol supporting non-interactive public outputs
Pseudorandom Correlation Functions for Multiparty Beaver Triples from Sparse LPN
We construct a pseudorandom correlation function (PCF) for oblivious linear evaluation (OLE) from sparse LPN over any finite field. The programmability property of our PCF implies a PCF for any multiparty degree-two correlation, e.g., Beaver triples. Our PCF is the first PCF for degree-two correlations from a well-established cryptographic assumption, apart from (inefficient) generic PCFs based on homomorphic secret sharing or fully homomorphic encryption. Our PCF outperforms the previously fastest PCF for Beaver triples (Boyle et al., Crypto 2022) by 3.2-28x.
We build on the recent pseudorandom correlation generator (PCG) by Miao et al. (Asiacrypt 2025) and extend it to a PCF using a recursive approach similar to Braun et al. (Asiacrypt 2025). Moreover, we extend these techniques to support authenticated degree-two correlations in the important two-party case
Fast Pseudorandom Correlation Functions from Sparse LPN
We introduce a new and efficient pseudorandom correlation function whose security reduces to the sparse LPN assumption in the random oracle model. Our construction is the first to achieve high concrete efficiency while relying on well-established assumptions: previous candidates either required introducing new assumptions, or had poor concrete performances. We complement our result with an in-depth analysis of the sparse LPN assumption, providing new insight on how to evaluate the strength of concrete sets of parameters
Parametric Study on Environmental Effects on Jacket Structure
Jacket typed structures arc most commonly used as supporting structure for deck
facilities which arc stahilixcd by leg piles driven through the seabed constructed
mainly in shallow water regions. 'their sizes ranges from three to eight legged
depending on the facilities to be installed on topsides. In jacket design phase. both
operational and environmental loads arc very important and must he investigated
intensively to ensure that the structures arc able to withstand the transmitted forces
during its design life. This report focused on studying the parameters of the
environmental loads and its effects on jackets during In-place. Results arc presented
in a graphical fort of parametric study in which it typical jacket type platform was
subjected to waves of varying height and period, increments of currents and wind
leads. Relationship between critical joint depth with water depth and total weight of
platfomts are also studied. Result shows that all the parameters involved have
significant effects on the jacket structure. Software called SACS Executive 5.2 will
he used to conduct the analysis throughout the project
Correlated Pseudorandomness from the Hardness of Quasi-Abelian Decoding
Secure computation often benefits from the use of correlated randomness to
achieve fast, non-cryptographic online protocols. A recent paradigm put forth
by Boyle (CCS 2018, Crypto 2019) showed how pseudorandom
correlation generators (PCG) can be used to generate large amounts of useful
forms of correlated (pseudo)randomness, using minimal interactions followed
solely by local computations, yielding silent secure two-party computation
protocols (protocols where the preprocessing phase requires almost no
communication). An additional property called programmability allows to extend
this to build N-party protocols. However, known constructions for programmable
PCG's can only produce OLE's over large fields, and use rather new splittable
Ring-LPN assumption.
In this work, we overcome both limitations. To this end, we introduce the
quasi-abelian syndrome decoding problem (QA-SD), a family of assumptions which
generalises the well-established quasi-cyclic syndrome decoding assumption.
Building upon QA-SD, we construct new programmable PCG's for OLE's over any
field with . Our analysis also sheds light on the security
of the ring-LPN assumption used in Boyle (Crypto 2020). Using
our new PCG's, we obtain the first efficient N-party silent secure computation
protocols for computing general arithmetic circuit over for any
.Comment: This is a long version of a paper accepted at CRYPTO'2
Correlated Pseudorandomness from the Hardness of Quasi-Abelian Decoding
Secure computation often benefits from the use of correlated randomness to achieve fast, non-cryptographic online protocols. A recent paradigm put forth by Boyle (CCS 2018, Crypto 2019) showed how pseudorandom correlation generators (PCG) can be used to generate large amounts of useful forms of correlated (pseudo)randomness, using minimal interactions followed solely by local computations, yielding silent secure two-party computation protocols (protocols where the preprocessing phase requires almost no communication). Furthermore, programmable PCG\u27s can be used similarly to generate multiparty correlated randomness to be used in silent secure N-party protocols. Previous works constructed very efficient (non-programmable) PCG\u27s for correlations such as random oblivious transfers. However, the situation is less satisfying for the case of random oblivious linear evaluation (OLE), which generalises oblivious transfers over large fields, and are a core resource for secure computation of arithmetic circuits. The state-of-the-art work of Boyle (Crypto 2020) constructed programmable PCG\u27s for OLE, but their work suffers from two important downsides: (1) it only generates OLE\u27s over large fields, and (2) it relies on relatively new splittable ring-LPN assumption, which lacks strong security foundations.
In this work, we construct new programmable PCG\u27s for the OLE correlation, that overcome both limitations. To this end, we introduce the quasi-abelian syndrome decoding problem (QA-SD), a family of assumptions which generalises the well-established quasi-cyclic syndrome decoding assumption. Building upon QA-SD, we construct new programmable PCG\u27s for OLE\u27s over any field with . Our analysis also sheds light on the security of the ring-LPN assumption used in Boyle (Crypto 2020). Using our new PCG\u27s, we obtain the first efficient N-party silent secure computation protocols for computing general arithmetic circuit over for any
