{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T20:48:15Z","timestamp":1777495695597,"version":"3.51.4"},"reference-count":22,"publisher":"Sociedade Brasileira de Computacao - SB","issue":"1","license":[{"start":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T00:00:00Z","timestamp":1775174400000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["iSys"],"abstract":"<jats:p>Em sistemas de informa\u00e7\u00e3o distribu\u00eddos, \u00e9 essencial garantir justi\u00e7a e privacidade na troca de itens digitais entre partes que n\u00e3o confiam plenamente umas nas outras. Nesses ambientes, V\u00e1rias entidades (usu\u00e1rios, organiza\u00e7\u00f5es, servi\u00e7os, dispositivos, etc.) interagem entre si, trocando dados, documentos ou valores digitais. Quando n\u00e3o h\u00e1 confian\u00e7a entre as partes envolvidas, surge o risco de injusti\u00e7a, ou seja, a possibilidade de uma delas obter vantagem indevida sobre a outra. Protocolos de troca justa foram desenvolvidos para assegurar que nenhuma das partes obtenha vantagem indevida, garantindo que a troca ocorra de maneira justa. Privacidade, outra propriedade fundamental, impede o vazamento de informa\u00e7\u00f5es confidenciais. No entanto, alcan\u00e7ar simultaneamente justi\u00e7a forte e privacidade ainda \u00e9 um desafio. Protocolos amplamente usados em sistemas de informa\u00e7\u00e3o para pagamentos online, \\textit{e-commerce} e assinaturas digitais garantem justi\u00e7a, mas comprometem a privacidade ao depender de terceiros centralizados que acessam diretamente os dados das partes, expondo informa\u00e7\u00f5es sens\u00edveis. Neste artigo, propomos a implementa\u00e7\u00e3o e an\u00e1lise de um protocolo com justi\u00e7a forte voltado a sistemas de informa\u00e7\u00e3o distribu\u00eddos, o qual garante que nenhum dos participantes obtenha ambos os itens e concede a cada parte o poder de cancelamento. O modelo adota um terceiro confi\u00e1vel dividido, formado por dois ambientes de execu\u00e7\u00e3o confi\u00e1veis (um para cada participante) e um \\textit{public bulletin board} usado apenas para sincroniza\u00e7\u00e3o. Essa arquitetura elimina intermedi\u00e1rios centralizados e preserva propriedades essenciais, como justi\u00e7a forte, cancelamento imediato e unilateral e privacidade. Este trabalho \u00e9 uma vers\u00e3o estendida do artigo apresentado no SBSeg 2025, incluindo novos resultados experimentais, verifica\u00e7\u00e3o formal com o SPIN \\textit{model checking}, e aprimoramentos de implementa\u00e7\u00e3o; contribuindo para o avan\u00e7o de solu\u00e7\u00f5es que protege a privacidade dos dados e interoper\u00e1veis em sistemas de informa\u00e7\u00e3o distribu\u00eddos.<\/jats:p>","DOI":"10.5753\/isys.2026.6859","type":"journal-article","created":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T15:01:30Z","timestamp":1777388490000},"source":"Crossref","is-referenced-by-count":0,"title":["Implementa\u00e7\u00e3o e An\u00e1lise de um Protocolo de Sincroniza\u00e7\u00e3o para Troca Justa com Justi\u00e7a Forte e Privacidade"],"prefix":"10.5753","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2845-4015","authenticated-orcid":false,"given":"Dhileane","family":"Quixabeira","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7674-854X","authenticated-orcid":false,"given":"Mailson","family":"Teles-Borges","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9514-6560","authenticated-orcid":false,"given":"Fabricia","family":"Roos-Frantz","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3740-7560","authenticated-orcid":false,"given":"Rafael","family":"Z. Frantz","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7960-0775","authenticated-orcid":false,"given":"Sandro","family":"Sawicki","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"3742","published-online":{"date-parts":[[2026,4,3]]},"reference":[{"key":"1","doi-asserted-by":"crossref","unstructured":"Asokan, N., Schunter, M., and Waidner, M. (1997). Optimistic protocols for fair exchange. In Proceedings of the 4th ACM Conference on Computer and Communications Security, pp. 7\u201317. [<a href=\"https:\/\/dl.acm.org\/doi\/10.1145\/266420.266426\" target=\"_blank\">link<\/a>].","DOI":"10.1145\/266420.266426"},{"key":"2","doi-asserted-by":"crossref","unstructured":"Asokan, N., Shoup, V., and Waidner, M. (2000). Optimistic fair exchange of digital signatures. 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