Publications

Gives the first attribute-based laconic function evaluation from DCR - the first computationally succinct secure computation from a group-based rather than lattice-based assumption. Extends fully homomorphic MACs to packed vector operations, and derives full laconic function evaluation from DCR+LWE plus a constrained PRF with a succinct master key.

Shows that sublinear-locality MPC can be maintained across an unbounded number of executions under adaptive corruption, not just a single run. Achieves polylog(n) locality for semi-honest/information-theoretic security and O~(n^(2/3)) locality for fail-stop/computational security, via reusable hidden-graph techniques.

Constructs a privately constrained PRF from DCR supporting constraints with polynomially bounded Waring rank, including puncturing - the first group-based construction to support puncturing at all. Builds on distributed-discrete-log techniques to non-interactively authenticate powers of linear combinations of shares.

Introduces a general template for garbling Boolean and arithmetic circuits with sublinear size from DCR, via a new HSS construction supporting “semi-private” inputs and a relinearisation technique for combining shares. Gives the first general-purpose garbled circuits with sublinear size that avoid indistinguishability obfuscation or fully homomorphic/attribute-based encryption.

Builds arithmetic garbling schemes from homomorphic-secret-sharing techniques for distributed discrete logarithms, achieving free addition gates. Obtains a 2-ciphertext-per-multiplication construction from IND-CPA security of the Damgard-Jurik cryptosystem, and a rate-1 construction assuming KDM security of the same scheme.

Strengthens the hash-then-evaluate PRF paradigm by replacing its random-oracle preprocessing step with a non-adaptive PRF under a public key, showing several weak-PRF candidates remain plausibly secure under this substitution. Applies the result to oblivious PRFs (for PAKE/PSI) and pseudorandom correlation functions (for silent OT extension).

Constructs pseudorandom correlation functions for OT correlations from constrained PRFs built around a weak PRF, instantiated via a tweaked Naor-Reingold PRF. Extends this to public-key PCFs with non-interactive key setup, reaching a throughput of 15-40k OT/s - roughly 4 orders of magnitude faster than prior public-key PCFs - and derives reusable DV-NIZKs as a side result.

Gives the first protocol for topology-hiding computation on general graphs from constant-round, constant-overhead two-party computation, rather than assumptions implying homomorphic encryption. Introduces “locally simulatable MPC” as a new technical tool of independent interest.

Constructs 1-key constrained pseudorandom functions from homomorphic secret sharing, identifying the HSS properties needed and showing most recent HSS schemes satisfy them. Yields the first constrained PRFs for inner-product and NC1 constraints from DCR, plus new secure-computation applications with silent or sublinear preprocessing.

Shows that sublinear-communication secure computation for more than two parties does not require fully homomorphic encryption, via a new framework built from function secret sharing for N parties. Gives sublinear protocols for various function classes in the 3- and 5-party settings, from assumptions not known to imply FHE.

Initiates a study of “low-end” obfuscation using simpler representations and information-theoretic security notions. Gives perfect indistinguishability obfuscation for decision trees and read-k arithmetic formulas via exact learning, and shows proper obfuscation of k-CNF formulas by k-CNF is impossible for k >= 3, assuming one-way functions.

Gives sublinear-communication protocols for general layered circuits from any decomposable 2-round rate-1 batch OT, yielding feasibility from Quadratic Residuosity plus polynomial-noise LPN. Also constructs single-server PIR with polylogarithmic communication from CDH, improving on the previous linear bound.

Introduces a homomorphic secret sharing scheme and pseudorandom correlation generator for log/loglog-local circuits from the super-polynomial hardness of LPN, yielding two-party secure computation for layered circuits with communication O(s/loglog s). Extends the set of assumptions known to break the circuit-size barrier beyond LWE, DDH, and DCR.

Studies the minimal assumptions needed for topology-hiding broadcast and anonymous broadcast, giving matching necessary and sufficient conditions across information-theoretic, key-agreement, and oblivious-transfer settings. Shows a dichotomy for 3+-party topology-hiding computation secure against one corruption: information-theoretic feasibility when all graphs are 2-connected, and a requirement of key agreement otherwise.

Journal version of the SCN 2024 paper of the same name. Strengthens the hash-then-evaluate PRF paradigm by replacing its random-oracle preprocessing with a non-adaptive PRF under a public key, with applications to oblivious PRFs and pseudorandom correlation functions.

Journal version of the TCC 2020 paper of the same name. Studies the minimal assumptions needed for topology-hiding broadcast and anonymous broadcast, giving matching necessary and sufficient conditions, and a dichotomy for 3+-party topology-hiding computation secure against one corruption.