When Chats Split Apart: Formalizing Temporal Communication Fragmentation and the CARTA Reconstruction Framework
Main Article Content
Abstract
When a phone fails and its owner keeps the messaging account running on a second device, the account's history can end up in two archives, each intact and each missing what the other holds. We call this Temporal Communication Fragmentation (TCF), a loss by non-union: no message is deleted, but the platform offers no operation that joins the two halves. WhatsApp's own documentation states that old and new chats cannot be merged. We define TCF by three jointly necessary and sufficient conditions and specify CARTA 1.1, a framework for reconstructing one archive from several. CARTA is an output contract owed to a reader who cannot check the result. Records that cannot be read unambiguously are quarantined with a typed reason, and a report gives each record's provenance, the conflicts and deduplication ambiguities found, and every setting used. We evaluated a reference implementation, CHAMP-Pipeline, on synthetic fragment sets with known ground truth. With its declared date inference it reproduced the ground truth in all 4,500 configurations of a parameter sweep; the invariants and the predicted outcome held in all 5,000 random configurations of two to four fragments; and reconstruction stayed exact at one million messages. A zone-offset advisory, frozen before testing, flagged all 2,800 misdeclared zones in a designed test of overlapping fragment pairs and 1,470 of 1,542 in random configurations, and raised false alarms in 2 of 600 correctly declared runs. A systematic search found 60 chat-merging tools; none fully provides more than 2 of the five output properties CARTA specifies. With a fragment's time zone left undeclared, every benchmarked tool and CHAMP-Pipeline produce the same duplicated and misdated records, and only CHAMP-Pipeline's report says so. All data are synthetic; no real archive has been reconstructed.
Article Details
Issue
Section
This work is licensed under a Creative Commons Attribution 4.0 International License.
How to Cite
References
Abraham, R., Schneider, J., & vom Brocke, J. (2019). Data governance: A conceptual framework, structured review, and research agenda. International Journal of Information Management, 49, 424–438. https://doi.org/10.1016/j.ijinfomgt.2019.07.008
Akif-b-Atif. (2026). The-Omar-Files [Computer software, commit 27faf12]. GitHub. https://github.com/Akif-b-Atif/The-Omar-Files
Almeida, P. S. (2025). Approaches to conflict-free replicated data types. ACM Computing Surveys, 57(2), 1–36. https://doi.org/10.1145/3695249
Anglano, C. (2014). Forensic analysis of WhatsApp Messenger on Android smartphones. Digital Investigation, 11(3), 201–213. https://doi.org/10.1016/j.diin.2014.04.003
Baas, J., Dastani, M., & Feelders, A. (2021). Exploiting transitivity constraints for entity matching in knowledge graphs (arXiv:2104.12589). arXiv. https://doi.org/10.48550/arXiv.2104.12589
Breitinger, F., Studiawan, H., & Hargreaves, C. (2025). SoK: Timeline based event reconstruction for digital forensics: Terminology, methodology, and current challenges. Forensic Science International: Digital Investigation, 53, 301932. https://doi.org/10.1016/j.fsidi.2025.301932
Chabot, Y., Bertaux, A., Nicolle, C., & Kechadi, M.-T. (2014a). A complete formalized knowledge representation model for advanced digital forensics timeline analysis. Digital Investigation, 11(Suppl. 2), S95–S105. https://doi.org/10.1016/j.diin.2014.05.009
Chabot, Y., Bertaux, A., Nicolle, C., & Kechadi, M.-T. (2014b). Automatic timeline construction and analysis for computer forensics purposes. In 2014 IEEE Joint Intelligence and Security Informatics Conference (pp. 276–279). IEEE. https://doi.org/10.1109/JISIC.2014.54
Chapman, A., Lauro, L., Missier, P., & Torlone, R. (2024). Supporting better insights of data science pipelines with fine-grained provenance. ACM Transactions on Database Systems, 49(2), 1–42. https://doi.org/10.1145/3644385
Dearman, D., & Pierce, J. S. (2008). "It's on my other computer!": Computing with multiple devices. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (pp. 767–776). ACM. https://doi.org/10.1145/1357054.1357177
Dreier, L. M., Vanini, C., Hargreaves, C. J., Breitinger, F., & Freiling, F. (2024). Beyond timestamps: Integrating implicit timing information into digital forensic timelines. Forensic Science International: Digital Investigation, 49, 301755. https://doi.org/10.1016/j.fsidi.2024.301755
Du, X., Hargreaves, C., Sheppard, J., & Scanlon, M. (2021). TraceGen: User activity emulation for digital forensic test image generation. Forensic Science International: Digital Investigation, 38, 301133. https://doi.org/10.1016/j.fsidi.2021.301133
Ehrlinger, L., & Wöß, W. (2022). A survey of data quality measurement and monitoring tools. Frontiers in Big Data, 5, 850611. https://doi.org/10.3389/fdata.2022.850611
frozenspider. (2026). chat-history-manager [Computer software, commit d1f6f88]. GitHub. https://github.com/frozenspider/chat-history-manager
Hornung, L., Bakker, C., Timbermont, B., van Dijk, R., van Beek, H., & Alechina, N. (2026). A formal model for forensically sound timestamp normalization. In 33rd International Symposium on Temporal Representation and Reasoning (TIME 2026) (OASIcs Vol. 146, pp. 10:1–10:21). Schloss Dagstuhl. https://doi.org/10.4230/OASIcs.TIME.2026.10
Hubers, C., Schwanen, T., & Dijst, M. (2008). ICT and temporal fragmentation of activities: An analytical framework and initial empirical findings. Tijdschrift voor Economische en Sociale Geografie, 99(5), 528–546. https://doi.org/10.1111/j.1467-9663.2008.00490.x
ISO/IEC. (2008). ISO/IEC 25012:2008 Software engineering — Software product Quality Requirements and Evaluation (SQuaRE) — Data quality model. ISO. https://www.iso.org/standard/35736.html
Karger, D. R., & Jones, W. (2006). Data unification in personal information management. Communications of the ACM, 49(1), 77–82. https://doi.org/10.1145/1107458.1107496
Kistler, J. J., & Satyanarayanan, M. (1992). Disconnected operation in the Coda File System. ACM Transactions on Computer Systems, 10(1), 3–25. https://doi.org/10.1145/146941.146942
krishnarajt. (2021). Whatsapp-Chat-File-Merger [Computer software, commit 138add0]. GitHub. https://github.com/krishnarajt/Whatsapp-Chat-File-Merger
log2timeline/plaso. (2026). Plaso [Computer software, commit 3733f4d]. GitHub. https://github.com/log2timeline/plaso
Moreau, L., Groth, P., Cheney, J., Lebo, T., & Miles, S. (2015). The rationale of PROV. Journal of Web Semantics, 35, 235–257. https://doi.org/10.1016/j.websem.2015.04.001
Onik, A. R., Brown, J., Walker, C., & Baggili, I. (2025). A systematic literature review of secure instant messaging applications from a digital forensics perspective. ACM Computing Surveys, 57(9), 1–36. https://doi.org/10.1145/3727641
Parker, D. S., Popek, G. J., Rudisin, G., Stoughton, A., Walker, B. J., Walton, E., Chow, J. M., Edwards, D., Kiser, S., & Kline, C. (1983). Detection of mutual inconsistency in distributed systems. IEEE Transactions on Software Engineering, SE-9(3), 240–247. https://doi.org/10.1109/TSE.1983.236733
Priestley, M., O'Donnell, F., & Simperl, E. (2023). A survey of data quality requirements that matter in ML development pipelines. Journal of Data and Information Quality, 15(2), 1–39. https://doi.org/10.1145/3592616
Saeedi, A., Nentwig, M., Peukert, E., & Rahm, E. (2018). Scalable matching and clustering of entities with FAMER. Complex Systems Informatics and Modeling Quarterly, 16, 61–83. https://doi.org/10.7250/csimq.2018-16.04
Saito, Y., & Shapiro, M. (2005). Optimistic replication. ACM Computing Surveys, 37(1), 42–81. https://doi.org/10.1145/1057977.1057980
Sapariya, M. (2026). CHAMP-Pipeline: Chat History Archival & Merge Pipeline (Specification and Reference Implementation of the CARTA Framework) (Version 0.2.0) [Computer software]. Zenodo. https://doi.org/10.5281/zenodo.23526491
Sebnembasak. (2026). wa-rescue [Computer software, commit c6dc551]. GitHub. https://github.com/sebnembasak/wa-rescue
Shapiro, M., Preguiça, N., Baquero, C., & Zawirski, M. (2011). A comprehensive study of convergent and commutative replicated data types (Research Report RR-7506). INRIA. https://inria.hal.science/inria-00555588
Sillence, E., Dawson, J. A., Brown, R. D., McKellar, K., & Neave, N. (2026). Digital hoarding and personal use digital data. Human–Computer Interaction, 41(1), 6–25. https://doi.org/10.1080/07370024.2023.2293001
Sokie. (2026). keepsake [Computer software, commit 89cdfb6]. GitHub. https://github.com/sokie/keepsake
Souibgui, M., Atigui, F., Zammali, S., Cherfi, S., & Ben Yahia, S. (2019). Data quality in ETL process: A preliminary study. Procedia Computer Science, 159, 676–687. https://doi.org/10.1016/j.procs.2019.09.223
Tarikab7. (2026). whatsapp-chat-merger [Computer software, commit 403c98e]. GitHub. https://github.com/tarikab7/whatsapp-chat-merger
Tseng, F.-C., Chiou, Z.-Y., Chuang, H.-H., Su, L.-T., Lin, Y.-H., Lin, Y.-R., Lee, Y.-C., Wang, P.-J., Chen, U.-D., & Chang, Y.-J. (2023). Multiple device users' actual and ideal cross-device usage for multi-stage notification-interactions: An ESM study addressing the usage gap and impacts of device context. In Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems (pp. 1–15). ACM. https://doi.org/10.1145/3544548.3580731
WhatsApp. (2026a). Can't transfer chat history [Help Center article 1039228717453239]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015115509/https://faq.whatsapp.com/1039228717453239/?locale=en_US&cms_platform=android
WhatsApp. (2026b). Can't move chats from an Android device to an iPhone [Help Center article 1195710084347483]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015131617/https://faq.whatsapp.com/1195710084347483/?locale=en_US&cms_platform=android
WhatsApp. (2026c). How to delete chats from your old phone [Help Center article 1233566054551746]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015132100/https://faq.whatsapp.com/1233566054551746/?locale=en_US&cms_platform=android
WhatsApp. (2026d). About inactive account deletion [Help Center article 828406668498455]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015153538/https://faq.whatsapp.com/828406668498455/?locale=en_US&cms_platform=android
WhatsApp. (2026e). How to restore your chat history [Help Center article 618575946635920]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015144935/https://faq.whatsapp.com/618575946635920/?locale=en_US&cms_platform=android
WhatsApp. (2026f). About linked devices [Help Center article 378279804439436]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015141959/https://faq.whatsapp.com/378279804439436/?locale=en_US&cms_platform=android
WhatsApp. (2026g). About message history on linked devices [Help Center article 653480766448040]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015145726/https://faq.whatsapp.com/653480766448040/?locale=en_US&cms_platform=android
WhatsApp. (2026h). How to export your chat history [Help Center article 1180414079177245]. Retrieved October 15, 2026, from https://web.archive.org/web/20261015131254/https://faq.whatsapp.com/1180414079177245/?locale=en_US&cms_platform=android
Wunder, J., Wash, R., Renaud, K., Oliveira, D. A., & Benenson, Z. (2025). Achieving resilience: Data loss and recovery on devices for personal use in three countries. In Proceedings of the 2025 CHI Conference on Human Factors in Computing Systems (pp. 1–26). ACM. https://doi.org/10.1145/3706598.3714202
Yu, W., & Ignat, C.-L. (2020). Conflict-free replicated relations for multi-synchronous database management at edge. In 2020 IEEE International Conference on Smart Data Services (pp. 113–121). IEEE. https://doi.org/10.1109/SMDS49396.2020.00021