Secret Sharing & Threshold Cryptography

Statements tagged with the secret-sharing area. This is a generated view, not a home directory – a statement can belong to several areas at once. See all statements for the full index, or the schema for what each column means.

Status Problem Tags
– AVPs Are Lengthy
Posed as Hypothesis 1.2 and offered both as a working hypothesis and as an ambitious target. Theorem 1.3 proves it implies super-polynomial lower bounds on sd-PIR, general secret sharing and fully-decomposable randomized encodings – for none of which a super-linear lower bound is currently known. The source adapts counting-based arguments to the model but does not reach the best-known bound for any primitive. 4 open
Garbled CircuitsPrivate Information RetrievalProof Size Lower BoundsRandomized Encodingslower-boundbarrier (ai)
– Sub-log Share Size for 2-out-of-\(n\)
The information-theoretic share size is exactly \(\log n\) and Shamir’s scheme matches it. The source proves a \((1/5)\log\log n\) lower bound for the computational setting with public information, leaving a \(\log n\) versus \(\log\log n\) gap, and proves that beating \(\log n\) by any constant factor is equivalent to a concrete planted clique-and-independent-set problem. 4 open
Average Case HardnessPlanted Subgraph ProblemsThreshold Secret Sharingtight-bound
– Conflict Checkable Codes Beyond Half-Singleton
Theorem 1.8 proves \(k\le(n-d+2)/2\) for codes that are both comparison-based and local-to-global consistent. Theorem 1.3 gives an almost-MDS conflict checkable code at \(k\ge n-d+1-\varepsilon\) which bypasses that bound, but it is neither comparison-based nor known to be local-to-global consistent. The conjecture names comparison-basedness as the culprit. It already holds at \(d=n-1\). 4 open
Code Based CryptographyLocally Testable CodesThreshold Secret Sharingseparationadaptation (ai)
– Threshold one-shot decryption without extractability
Open: whether threshold one-shot decryption (for every corruption threshold \(f<1/2\)) follows from one-shot signatures and an ordinary, non-extractable witness encryption scheme. The one known construction needs the witness-encryption extractor to run its security reduction, and the source paper leaves open whether extractability can be weakened or dropped altogether. 4 open
One Shot SignaturesWitness EncryptionassumptionIOG
– Perfect FASS at 3-out-of-5
Statistical and computational FASS are settled by the source and prior work. The perfect version is stated by the source to be open for every reconstruction threshold \(3\le t\le n-2\), and open even for the weaker multi-dealer notion, with 3-out-of-5 the smallest open case. Con has settled the perfect case for gap threshold structures. 5 open
AnonymityThreshold Secret Sharingcharacterizationadaptation (ai)
– WP Threshold Share Size
The \(2\)-out-of-\(n\) case is settled: Beimel and Franklin give \(1/n\)-weakly-private schemes with share size 2, against \(\Theta(\log n)\) for perfect privacy. The source states large thresholds are open and asks specifically about \((n-1)\)-out-of-\(n\) at share size \(o(\log n)\). 5 open
Threshold Secret Sharingcharacterizationadaptation (ai)
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