[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-82090-en":3,"doc-seo-82090-105":30,"detail-sidebar-cat-0-en-105":91},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":21,"is_downloadable":21,"audit_status":21,"page_count":22,"language":23,"language_code":24,"site_id":25,"html_lang":24,"table_of_contents":26,"faqs":27,"seo_title":13,"seo_description":14,"update_tm":28,"read_time":29},82090,1374391975076,"Riley","https://ap-avatar.wpscdn.com/avatar/14000253ca4ec9f6853?x-image-process=image/resize,m_fixed,w_180,h_180&k=1783305029341752051",8,"Research & Report","Keyless Covert Communication Over Quantum MACs with General Message Sets","Study of keyless covert classical communication over quantum multiple-access channels (MACs) with arbitrary numbers of transmitters and general message sets. A fully quantum MAC model is analyzed to prove feasibility of achieving a positive covert rate, along with one-shot and asymptotic achievable rate regions. For classical-quantum MACs with general message sets under deterministic encoding, the covert capacity is characterized. Results extend and recover known special cases and are applied via examples including MACs with a helper: finite-dimensional, classical Gaussian, and single-mode bosonic settings.","Keyless Covert Communication Over Quantum MACs with General Message Sets  \nHassan ZivariFard and Xiaodong Wang  \narXiv :2607 .08898v 1 [ cs .IT] 9 Jul 2026  \nAbstract—We study covert classical communication over quantum multiple-access channels (MACs) with general message sets. Specifically, we consider a fully quantum MAC with arbitrary message sets and an arbitrary number of transmitters. We demonstrate the feasibility of achieving a positive covert rate over this channel and establish general one-shot and asymptotic achievable rate regions. For classical-quantum MACs with general message sets, we establish the covert capacity, when the transmitters are restricted to deterministic encoding. Our result recovers, as a special case, known results for classical communication over classical MACs with general message sets, covert communication of a classical message over a classical channel with two transmitters, and classical communication over quantum MACs. We provide three examples of MACs to which our results can be applied, either directly or indirectly, to achieve positive covert rates. Specifically, we first study covert communication over a finite-dimensional MAC with a helper. We then analyze a classical Gaussian MAC with a helper and derive its covert capacity. Finally, we extend the analysis to a singlemode bosonic MAC with a helper and show that positive covert rates can also be achieved in this setting. To the best of our knowledge, this is the first work to achieve positive-rate covert communication over both classical and quantum MACs.  \nI. INTRODUCTION  \nThe objective of covert communication is to render the transmission of messages undetectable [2]–[5] . In a point-topoint classical Discrete Memoryless Channel (DMC), it is well established that it is possible to reliably and covertly transmit at most O ( √n) bits over n channel uses [4], [5], provided that the encoder and decoder share a secret key of size O ( √ n)  bits [4] . Also, covert communication over discrete memoryless MACs is studied in [6], where each transmitter shares a secret key with the receiver. The authors show that each transmitter can transmit on the order of √n reliable and covert bits per n channel uses. We note that positive covert communication rates can be achieved for point-to-point classical DMCs [5] only when the symbol x0 ∈ X , transmitted by the sender in the no-communication mode, is redundant, which implies that the distribution induced on the warden’s channel observation by x0 ∈ X can also be induced using the channel input symbols {x ∈ X : x  x0 } . Building on this result, it has been demonstrated that positive covert rates can also be achieved over classical channels under various scenarios: (i) when a friendly jammer is present and there is a secret key shared between the legitimate terminals [7]–[10],(ii) when the transmitter has access to Channel State Information (CSI) [11],[12],(iii) when the transmitter has access to Action-Dependent  \nThe authors are with the Department of Electrical Engineering, Columbia University, New York, NY 10027 . This work is supported in part by the U.S. Office of Naval Research (ONR) under grant N000142112155 . E-mails:{hz2863, [xw2008](xw2008}@columbia.edu. Part)[}](xw2008}@columbia.edu. Part)[@columbia.edu. Part](xw2008}@columbia.edu. Part) of this work is presented at the 2025 IEEE International Symposium on Information Theory [1] . Part of this work is submitted to the 2026 IEEE Information Theory Workshop.  \nState Information (ADSI) [13], (iv) when the warden has uncertainty about the statistical characteristics of its channel and the transmitter and the receiver share a secret key [14],[15], (v) and when there is a cooperative user who knows either the message or the transmitter’s codeword [8],[10],[13] .  \nExisting works on covert communication over quantum channels show that optimal rates obey the square root law. Specifically, covert communication over bosonic channels is considered in ","cbCailjgrkXSKGld","https://ap.wps.com/l/cbCailjgrkXSKGld","pdf",763574,2,1,30,"English","en",105,"# Abstract\n# Introduction\n## Covert communication objective and square-root law\n## Prior classical and quantum covert results\n## Keyless covert communication over quantum MACs (this work)","[{\"question\":\"What channel model is studied for covert communication?\",\"answer\":\"The work studies keyless covert classical communication over quantum multiple-access channels (MACs) with an arbitrary number of transmitters and general message sets.\"},{\"question\":\"How is positive covert communication rate achieved in this setting?\",\"answer\":\"The paper demonstrates the feasibility of achieving a positive covert rate over the fully quantum MAC and develops both one-shot and asymptotic achievable rate regions.\"},{\"question\":\"What does the paper conclude for classical-quantum MACs with deterministic encoding?\",\"answer\":\"It establishes the covert capacity for classical-quantum MACs with general message sets when transmitters are restricted to deterministic encoders.\"}]",1784178156,76,{"code":4,"msg":31,"data":32},"ok",{"site_id":25,"language":24,"slug":33,"title":13,"keywords":34,"description":14,"schema_data":35,"social_meta":86,"head_meta":88,"extra_data":90,"updated_unix":28},"keyless-covert-communication-over-quantum-macs-with-general-message-sets","",{"@graph":36,"@context":85},[37,53,68],{"@type":38,"itemListElement":39},"BreadcrumbList",[40,44,47,50],{"item":41,"name":42,"@type":43,"position":21},"https://docshare.wps.com","Home","ListItem",{"item":45,"name":46,"@type":43,"position":20},"https://docshare.wps.com/document/","Document",{"item":48,"name":12,"@type":43,"position":49},"https://docshare.wps.com/document/research-report/",3,{"item":51,"name":13,"@type":43,"position":52},"https://docshare.wps.com/document/keyless-covert-communication-over-quantum-macs-with-general-message-sets/82090/",4,{"url":51,"name":13,"@type":54,"author":55,"headline":13,"publisher":57,"fileFormat":60,"inLanguage":24,"description":14,"dateModified":61,"datePublished":62,"encodingFormat":60,"isAccessibleForFree":63,"interactionStatistic":64},"DigitalDocument",{"name":9,"@type":56},"Person",{"url":41,"name":58,"@type":59},"DocShare","Organization","application/pdf","2026-07-20","2026-07-16",true,{"@type":65,"interactionType":66,"userInteractionCount":20},"InteractionCounter",{"@type":67},"ViewAction",{"@type":69,"mainEntity":70},"FAQPage",[71,77,81],{"name":72,"@type":73,"acceptedAnswer":74},"What channel model is studied for covert communication?","Question",{"text":75,"@type":76},"The work studies keyless covert classical communication over quantum multiple-access channels (MACs) with an arbitrary number of transmitters and general message sets.","Answer",{"name":78,"@type":73,"acceptedAnswer":79},"How is positive covert communication rate achieved in this setting?",{"text":80,"@type":76},"The paper demonstrates the feasibility of achieving a positive covert rate over the fully quantum MAC and develops both one-shot and asymptotic achievable rate regions.",{"name":82,"@type":73,"acceptedAnswer":83},"What does the paper conclude for classical-quantum MACs with deterministic encoding?",{"text":84,"@type":76},"It establishes the covert capacity for classical-quantum MACs with general message sets when transmitters are restricted to deterministic 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