{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/136969"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/136969","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Metadata-Aware Memory Security","abstract":"Cloud computing reduces infrastructure costs by allowing applications to run on shared servers, but it introduces critical memory security challenges, as users lack control over the underlying hardware and the software co-residing on the same server. One security challenge is physical attacks on memory, such as memory bus snooping, which is addressed through hardware-based memory encryption. While effective, encryption often causes significant time (performance) overhead, especially for irregular workloads. Another challenge is side channels caused by memory sharing, where attackers infer sensitive data through cache or DRAM reuse. As a result, cloud providers often disable memory sharing, sacrificing space (capacity) for security. This thesis focuses on reducing the cost of cloud memory security by optimizing metadata management. It minimizes the time overhead of memory encryption by improving how encryption-related metadata (e.g., write counters) is encoded and accessed. It also addresses the space overhead of memory isolation by novel coding of metadata for memory sharing - physical page number (PPN) of shared page, enabling secure memory sharing without sacrificing efficiency. By managing both types of metadata intelligently, this work reduces the time and space costs of secure cloud memory, offering practical solutions for efficient and secure cloud systems.","abstract_html":"Cloud computing reduces infrastructure costs by allowing applications to run on shared servers, but it introduces critical memory security challenges, as users lack control over the underlying hardware and the software co-residing on the same server. One security challenge is physical attacks on memory, such as memory bus snooping, which is addressed through hardware-based memory encryption. While effective, encryption often causes significant time (performance) overhead, especially for irregular workloads. Another challenge is side channels caused by memory sharing, where attackers infer sensitive data through cache or DRAM reuse. As a result, cloud providers often disable memory sharing, sacrificing space (capacity) for security. This thesis focuses on reducing the cost of cloud memory security by optimizing metadata management. It minimizes the time overhead of memory encryption by improving how encryption-related metadata (e.g., write counters) is encoded and accessed. It also addresses the space overhead of memory isolation by novel coding of metadata for memory sharing - physical page number (PPN) of shared page, enabling secure memory sharing without sacrificing efficiency. By managing both types of metadata intelligently, this work reduces the time and space costs of secure cloud memory, offering practical solutions for efficient and secure cloud systems.","abstract_has_math":false,"creators":["Wang, Xin"],"institution":"Virginia Tech","degree_name":"Doctor of Philosophy","degree_level":"doctoral","degree_discipline":"Computer Science & Applications","degree_department":"Computer Science and#38; Applications","school":null,"contributors":[],"advisors":[],"committee_chairs":["Jian, Xun"],"committee_members":["Nikolopoulos, Dimitrios S.","Yao, Danfeng","Jung, Changhee","Hicks, Matthew"],"year":2025,"date_issued":"2025-08-05","date_published":"2025-08-05","updated_at":"2026-07-22T22:20:21Z","subjects":["Memory Security","Cache","Memory","Computer Architecture."],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44377"],"render_values":[{"text":"vt_gsexam:44377","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10919/136969","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Jian, Xun"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Nikolopoulos, Dimitrios S.","Yao, Danfeng","Jung, Changhee","Hicks, Matthew"]},{"key":"dc:contributor.department","label":"Department","values":["Computer Science and#38; Applications"]},{"key":"dc:creator","label":"Author","values":["Wang, Xin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-08-06T08:00:33Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-08-06T08:00:33Z"]},{"key":"dc:date.issued","label":"Date","values":["2025-08-05"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Computer Science & Applications"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Memory Security","Cache","Memory","Computer Architecture."]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:44377"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10919/136969"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Cloud computing reduces infrastructure costs by allowing applications to run on shared servers, but it introduces critical memory security challenges, as users lack control over the underlying hardware and the software co-residing on the same server. One security challenge is physical attacks on memory, such as memory bus snooping, which is addressed through hardware-based memory encryption. While effective, encryption often causes significant time (performance) overhead, especially for irregular workloads. Another challenge is side channels caused by memory sharing, where attackers infer sensitive data through cache or DRAM reuse. As a result, cloud providers often disable memory sharing, sacrificing space (capacity) for security. This thesis focuses on reducing the cost of cloud memory security by optimizing metadata management. It minimizes the time overhead of memory encryption by improving how encryption-related metadata (e.g., write counters) is encoded and accessed. It also addresses the space overhead of memory isolation by novel coding of metadata for memory sharing - physical page number (PPN) of shared page, enabling secure memory sharing without sacrificing efficiency. By managing both types of metadata intelligently, this work reduces the time and space costs of secure cloud memory, offering practical solutions for efficient and secure cloud systems."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["Cloud computing helps companies lower costs by sharing servers across many users, but this shared model introduces new risks to data privacy. Sensitive information stored in memory— the area where active data is kept—can be exposed through physical access or through side channels. Physical access refers to scenarios where malicious actors, such as disgruntled cloud employees or intruders with hardware-level access, can directly probe memory hardware to extract or tamper with data. Side channels are indirect clues, such as timing differences, that attackers can observe to infer private data without directly accessing it. Cloud systems traditionally defend memory by using encryption to prevent physical at- tacks and by disabling memory sharing to avoid side-channel leaks. While effective, these methods come at a cost—encryption slows down memory access, and disabling sharing in- creases memory usage. This research aims to make cloud memory both secure and efficient. It reduces the performance overhead of encryption through better hardware handling and enables safe memory sharing without leaking information through side channels. These techniques help protect user data while maintaining high system performance."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Doctor of Philosophy"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Metadata-Aware Memory Security"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Jian, Xun"],"dc:contributor.committeemember":["Nikolopoulos, Dimitrios S.","Yao, Danfeng","Jung, Changhee","Hicks, Matthew"],"dc:contributor.department":["Computer Science and#38; Applications"],"dc:creator":["Wang, Xin"],"dc:date.accessioned":["2025-08-06T08:00:33Z"],"dc:date.available":["2025-08-06T08:00:33Z"],"dc:date.issued":["2025-08-05"],"dc:description.abstract":["Cloud computing reduces infrastructure costs by allowing applications to run on shared servers, but it introduces critical memory security challenges, as users lack control over the underlying hardware and the software co-residing on the same server. One security challenge is physical attacks on memory, such as memory bus snooping, which is addressed through hardware-based memory encryption. While effective, encryption often causes significant time (performance) overhead, especially for irregular workloads. Another challenge is side channels caused by memory sharing, where attackers infer sensitive data through cache or DRAM reuse. As a result, cloud providers often disable memory sharing, sacrificing space (capacity) for security. This thesis focuses on reducing the cost of cloud memory security by optimizing metadata management. It minimizes the time overhead of memory encryption by improving how encryption-related metadata (e.g., write counters) is encoded and accessed. It also addresses the space overhead of memory isolation by novel coding of metadata for memory sharing - physical page number (PPN) of shared page, enabling secure memory sharing without sacrificing efficiency. 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Cloud systems traditionally defend memory by using encryption to prevent physical at- tacks and by disabling memory sharing to avoid side-channel leaks. While effective, these methods come at a cost—encryption slows down memory access, and disabling sharing in- creases memory usage. This research aims to make cloud memory both secure and efficient. It reduces the performance overhead of encryption through better hardware handling and enables safe memory sharing without leaking information through side channels. These techniques help protect user data while maintaining high system performance."],"dc:description.degree":["Doctor of Philosophy"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:44377"],"dc:identifier.uri":["https://hdl.handle.net/10919/136969"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Memory Security","Cache","Memory","Computer Architecture."],"dc:title":["Metadata-Aware Memory Security"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Computer Science & Applications"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:21Z"}