{"schema_version":"0.1","map_id":"paper-25-map","publication_id":25,"publication_anchor":"paper-25","slug":"paper-25","canonical_path":"/knowledge/papers/paper-25/","machine_path":"/knowledge/papers/paper-25.json","root_node_id":"paper-25","stage":"mapped_draft","contribution_type_vocabulary_version":"0.1","contribution_types":["protocol","scheme"],"title":"How to Withstand Mobile Virus Attacks, Revisited","year":2014,"status":"Published","venue":"ACM Symposium on Principles of Distributed Computing (PODC)","topic":"secure-encrypted-computation","labels":["Theory"],"authors":["Joshua Baron","Karim Eldefrawy","Joshua Lampkins","Rafail Ostrovsky"],"keywords":["proactive MPC","mobile adversaries","packed secret sharing"],"research_question":"Can proactive secure multiparty computation against an adaptive mobile adversary achieve universal composability, near-linear communication, and near-optimal corruption thresholds despite the need to refresh all long-lived state?","central_answer":"The paper introduces packed proactive secret sharing with constant amortized communication per secret, a Block-Redistribute protocol that refreshes and restores packed shares, and a layer-by-layer proactive MPC protocol; party virtualization raises the reported perfect-security threshold toward one third and the statistical threshold toward one half.","curation":{"drafted_at":"2026-07-11","drafted_by":[{"actor_type":"ai","name":"OpenAI Codex","role":"full-text extraction, theorem/assumption mapping, evidence linking, and initial assessment"}],"method":"Source-grounded review of the complete 34-page UCLA author-hosted full version, including definitions, protocol specifications, complexity analysis, UC ideal functionalities, and appendix proofs; PDF pages 1 and 12 were rendered and visually inspected.","source_scope":"full_source_audit","approval":{"status":"pending","note":"AI-authored source-linked map awaiting author verification. The paper proofs were mapped but not independently reproved or machine checked."}},"sources":[{"id":"source-paper-25-fulltext","type":"scholarly_article","title":"How to Withstand Mobile Virus Attacks, Revisited (author-hosted full version)","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf","media_type":"application/pdf","sha256":"6035df99829f970f28ad4522659ab5887de378dd28d1e220095e548711ccb4cd","page_count":34,"provenance_category":"author","version_note":"Complete author version with appendices; not compared line by line with the ten-page PODC proceedings version."},{"id":"source-paper-25-author-origin","type":"author_copy","title":"UCLA author copy","url":"https://web.cs.ucla.edu/~rafail/PUBLIC/167.pdf"},{"id":"source-paper-25-official","type":"publication_record","title":"ACM PODC publication record","url":"https://doi.org/10.1145/2611462.2611474"},{"id":"source-paper-25-citations","type":"scholarly_index","title":"OpenAlex work record for paper #25","url":"https://openalex.org/W2029416521","accessed_at":"2026-07-11"}],"source_anchors":[{"id":"anchor-paper-25-problem","source_id":"source-paper-25-fulltext","label":"Problem, roadblocks, contributions, and headline bounds","locator":"Abstract and Sections 1.2-1.4, PDF pages 1-5","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=1"},{"id":"anchor-paper-25-model","source_id":"source-paper-25-fulltext","label":"Proactive UC model, phases, erasures, and baseline parameters","locator":"Section 2, PDF pages 5-7","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=5"},{"id":"anchor-paper-25-redistribution","source_id":"source-paper-25-fulltext","label":"Packed sharing and Block-Redistribute","locator":"Sections 3.2-3.3 and Theorem 1, PDF pages 8-11","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=8"},{"id":"anchor-paper-25-pmpc","source_id":"source-paper-25-fulltext","label":"Layer-by-layer PMPC protocol and complexity","locator":"Sections 3.4-3.5 and Figure 1, PDF pages 11-13","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=11"},{"id":"anchor-paper-25-theorems","source_id":"source-paper-25-fulltext","label":"Perfect and statistical proactive-security theorems","locator":"Theorems 2-3, PDF page 13; Theorem 12, PDF page 34","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=13"},{"id":"anchor-paper-25-uc-definition","source_id":"source-paper-25-fulltext","label":"Exact proactive UC execution and security definitions","locator":"Appendix A, PDF pages 15-18","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=15"},{"id":"anchor-paper-25-proofs","source_id":"source-paper-25-fulltext","label":"Redistribution and PMPC proof chain","locator":"Appendices B and D, PDF pages 18-21 and 26-29","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=18"},{"id":"anchor-paper-25-virtualization","source_id":"source-paper-25-fulltext","label":"Party virtualization and near-optimal thresholds","locator":"Appendix E, PDF pages 29-34","url":"/pubs/2014/how-to-withstand-mobile-virus-attacks-revisited.pdf#page=29"},{"id":"anchor-paper-25-publication","source_id":"source-paper-25-official","label":"Official ACM publication record","locator":"PODC 2014, pages 293-302","url":"https://doi.org/10.1145/2611462.2611474"},{"id":"anchor-paper-25-citations","source_id":"source-paper-25-citations","label":"Dated OpenAlex citation snapshot","locator":"cited_by_count = 37, accessed 2026-07-11","url":"https://openalex.org/W2029416521"}],"nodes":[{"id":"paper-25","kind":"paper","parent_id":null,"order":1,"epistemic_status":"published","title":"How to Withstand Mobile Virus Attacks, Revisited","summary":"A proactive MPC construction that refreshes computation state against mobile corruption using packed proactive secret sharing and communication-efficient redistribution.","source_anchor_ids":["anchor-paper-25-problem"]},{"id":"paper-25-question","kind":"question","parent_id":"paper-25","order":1,"epistemic_status":"research_question","title":"Research question","summary":"Can the communication improvements of stationary-fault MPC survive a model in which an adversary eventually corrupts every party, subject only to a per-stage rate bound?","source_anchor_ids":["anchor-paper-25-problem"]},{"id":"paper-25-answer","kind":"contribution","parent_id":"paper-25","order":2,"epistemic_status":"source_asserted","title":"Central answer","summary":"Pack Θ(n) secrets into polynomial sharings, refresh and restore them with hyper-invertible-matrix checks, and evaluate a transformed circuit layer by layer with redistribution after every layer.","source_anchor_ids":["anchor-paper-25-redistribution","anchor-paper-25-pmpc"]},{"id":"paper-25-scope","kind":"scope","parent_id":"paper-25","order":3,"epistemic_status":"defined","title":"Proactive execution model","summary":"Parties communicate synchronously over perfectly secure point-to-point channels and broadcast, erase old state, and alternate operation with refreshment stages.","source_anchor_ids":["anchor-paper-25-model","anchor-paper-25-uc-definition"]},{"id":"paper-25-scope-adversary","kind":"threat_model","parent_id":"paper-25-scope","order":1,"epistemic_status":"defined","title":"Active adaptive mobile adversary","summary":"The adversary may adaptively corrupt different parties over time, but at most the stated threshold per stage; a party corrupted during a refresh counts in both adjacent stages.","source_anchor_ids":["anchor-paper-25-model","anchor-paper-25-uc-definition"]},{"id":"paper-25-scope-recovery","kind":"assumption","parent_id":"paper-25-scope","order":2,"epistemic_status":"assumed","title":"Reboot and erasure assumptions","summary":"Corrupted parties can be rebooted to a pristine state with global computation information and secure-channel access, and honest-period randomness and erased state remain unrecoverable; selecting whom to reboot is outside the protocol.","source_anchor_ids":["anchor-paper-25-problem","anchor-paper-25-model"]},{"id":"paper-25-method","kind":"method","parent_id":"paper-25","order":4,"epistemic_status":"specified","title":"Construction stack","summary":"The protocol composes packed sharing, proactive redistribution, circuit normalization and permutation, per-layer arithmetic, and party virtualization.","source_anchor_ids":["anchor-paper-25-redistribution","anchor-paper-25-pmpc","anchor-paper-25-virtualization"]},{"id":"paper-25-method-ppss","kind":"component","parent_id":"paper-25-method","order":1,"epistemic_status":"specified_and_proved","title":"Packed proactive secret sharing","summary":"Multiple secrets occupy evaluation points of one polynomial; random masking polynomials and hyper-invertible matrices amortize refresh and checking to O(1) communication per secret.","source_anchor_ids":["anchor-paper-25-problem","anchor-paper-25-redistribution"]},{"id":"paper-25-method-redistribute","kind":"component","parent_id":"paper-25-method","order":2,"epistemic_status":"specified_and_proved","title":"Block-Redistribute","summary":"Three phases rerandomize packed sharings, verifiably double-share state, and reconstruct current shares for rebooted parties using Berlekamp-Welch recovery.","source_anchor_ids":["anchor-paper-25-redistribution","anchor-paper-25-proofs"]},{"id":"paper-25-method-pmpc","kind":"component","parent_id":"paper-25-method","order":3,"epistemic_status":"specified_and_proved","title":"Layer-by-layer PMPC","summary":"Inputs are robustly shared; secrets are permuted for each homogeneous addition or multiplication layer; obsolete state is erased; all live sharings are redistributed after every layer before final reconstruction.","source_anchor_ids":["anchor-paper-25-pmpc"]},{"id":"paper-25-claims","kind":"claim_group","parent_id":"paper-25","order":5,"epistemic_status":"proved_conditional","title":"Principal theorems","summary":"The paper states UC-security and communication bounds under explicit network, erasure, circuit-width, and corruption-rate conditions.","source_anchor_ids":["anchor-paper-25-redistribution","anchor-paper-25-theorems"]},{"id":"paper-25-claim-redistribution","kind":"claim","parent_id":"paper-25-claims","order":1,"epistemic_status":"proved_conditional","title":"Redistribution theorem","summary":"Theorem 1 states perfect UC realization of the redistribution functionality against adaptive corruption threshold n/8, assuming secure point-to-point and broadcast channels, with O(W + poly(n)) communication for W secrets.","source_anchor_ids":["anchor-paper-25-redistribution","anchor-paper-25-proofs"]},{"id":"paper-25-claim-pmpc","kind":"claim","parent_id":"paper-25-claims","order":2,"epistemic_status":"proved_conditional","title":"Base PMPC theorem","summary":"For an n-party arithmetic circuit at least Ω(n) gates wide, Theorem 2 gives perfect proactive UC security against an active adaptive adversary corrupting fewer than n/8 parties per stage.","source_anchor_ids":["anchor-paper-25-theorems","anchor-paper-25-proofs"]},{"id":"paper-25-claim-thresholds","kind":"claim","parent_id":"paper-25-claims","order":3,"epistemic_status":"proved_conditional","title":"Virtualized thresholds","summary":"Theorem 3 raises perfect security to any constant corruption fraction δ < 1/3, while the statistical variant in Theorem 12 supports δ < 1/2.","source_anchor_ids":["anchor-paper-25-theorems","anchor-paper-25-virtualization"]},{"id":"paper-25-claim-complexity","kind":"claim","parent_id":"paper-25-claims","order":4,"epistemic_status":"analytically_supported","title":"Near-linear communication","summary":"The final virtualized construction is reported with communication O(C log² C polylog n + D poly(n) log² C), where C and D are circuit size and depth; packed share maintenance is constant amortized per secret.","source_anchor_ids":["anchor-paper-25-problem","anchor-paper-25-pmpc"]},{"id":"paper-25-evidence","kind":"evidence_group","parent_id":"paper-25","order":6,"epistemic_status":"formal_paper_evidence","title":"Evidence chain","summary":"The source supplies ideal functionalities, explicit protocols, complexity derivations, simulators for redistribution, an inductive PMPC simulation, and committee-based threshold amplification.","source_anchor_ids":["anchor-paper-25-uc-definition","anchor-paper-25-proofs","anchor-paper-25-virtualization"]},{"id":"paper-25-evidence-proof","kind":"evidence","parent_id":"paper-25-evidence","order":1,"epistemic_status":"paper_proof_not_machine_checked","title":"UC proof structure","summary":"The appendices compare real and ideal executions, construct simulators, and use layer induction plus prior subprotocol security; this audit checked statement/assumption alignment but did not rederive every simulation step.","source_anchor_ids":["anchor-paper-25-proofs"]},{"id":"paper-25-boundaries","kind":"limitation_group","parent_id":"paper-25","order":7,"epistemic_status":"material","title":"Trusted boundaries and limitations","summary":"The guarantees rely on synchrony, secure channels, broadcast, erasures, reliable pristine reboot, stage-rate enforcement, and sufficiently wide arithmetic circuits.","source_anchor_ids":["anchor-paper-25-model","anchor-paper-25-theorems"]},{"id":"paper-25-boundary-systems","kind":"limitation","parent_id":"paper-25-boundaries","order":1,"epistemic_status":"assumed","title":"Recovery mechanism is external","summary":"The paper does not specify how compromise is detected, how parties are selected and securely rebooted, or how proactive PKI/secure channels and broadcast are implemented.","source_anchor_ids":["anchor-paper-25-problem","anchor-paper-25-model"]},{"id":"paper-25-boundary-evidence","kind":"limitation","parent_id":"paper-25-boundaries","order":2,"epistemic_status":"no_empirical_evaluation","title":"No implementation evaluation","summary":"Evidence is theoretical; the audited version does not provide code, benchmarks, network measurements, or concrete parameter sizing.","source_anchor_ids":["anchor-paper-25-pmpc"]},{"id":"paper-25-artifacts","kind":"artifact_group","parent_id":"paper-25","order":8,"epistemic_status":"full_text_available","title":"Artifacts and resources","summary":"A fixed local mirror of the 34-page author full version and the ACM publication record are available; no implementation repository was identified.","source_anchor_ids":["anchor-paper-25-problem","anchor-paper-25-publication"]},{"id":"paper-25-scrutiny","kind":"scrutiny","parent_id":"paper-25","order":9,"epistemic_status":"publication_recorded","title":"External scrutiny","summary":"The work was published at ACM PODC 2014; review reports, independent proof audits, and implementations were not examined.","source_anchor_ids":["anchor-paper-25-publication"]},{"id":"paper-25-lineage","kind":"lineage","parent_id":"paper-25","order":10,"epistemic_status":"documented","title":"Research lineage","summary":"The construction revisits the Ostrovsky-Yung proactive model using packed-sharing and hyper-invertible-matrix techniques from later efficient MPC, and it directly precedes the dynamic-group protocol in paper #28.","source_anchor_ids":["anchor-paper-25-problem"]}],"relations":[{"id":"relation-paper-25-answer-addresses-question","type":"addresses","from_id":"paper-25-answer","to_id":"paper-25-question"},{"id":"relation-paper-25-method-realizes-answer","type":"realizes","from_id":"paper-25-method","to_id":"paper-25-answer"},{"id":"relation-paper-25-proof-supports-redistribution","type":"supports","from_id":"paper-25-evidence-proof","to_id":"paper-25-claim-redistribution"},{"id":"relation-paper-25-proof-supports-pmpc","type":"supports","from_id":"paper-25-evidence-proof","to_id":"paper-25-claim-pmpc"},{"id":"relation-paper-25-adversary-qualifies-pmpc","type":"qualifies","from_id":"paper-25-scope-adversary","to_id":"paper-25-claim-pmpc"},{"id":"relation-paper-25-recovery-qualifies-pmpc","type":"qualifies","from_id":"paper-25-scope-recovery","to_id":"paper-25-claim-pmpc"},{"id":"relation-paper-25-boundaries-qualify-claims","type":"qualifies","from_id":"paper-25-boundaries","to_id":"paper-25-claims"},{"id":"relation-paper-25-artifacts-enable-audit","type":"enables_audit_of","from_id":"paper-25-artifacts","to_id":"paper-25-evidence"}],"assessment":{"id":"paper-25-assessment-2026-07-11","rubric_version":"0.2","assessed_at":"2026-07-11","status":"ai_draft_author_review_pending","note":"These dimensions describe documented support and process, not truth, correctness, or a universal ranking. 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