defy: a deniable, encrypted file system for log structured...
TRANSCRIPT
![Page 1: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/1.jpg)
DEFY: A Deniable, Encrypted File System for Log Structured Storage
WRITTEN BY: PRESENTED BY:
TIMOTHY PETERS NICHOLAS BURTON
MARK GONDREE
ZACHARY PETERSON
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What is encryption?
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Why hide encryption?
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Previous Work on the Matter
u Anderson and others…
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Previous Work on the Matter
u Anderson and others…
u StegFS, McDonald and Kuhn
![Page 6: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/6.jpg)
Previous Work on the Matter
u Anderson and others…
u StegFS, McDonald and Kuhn
u StegFS, Pang, Tan, and Zhou
![Page 7: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/7.jpg)
Previous Work on the Matter
u Anderson and others…
u StegFS, McDonald and Kuhn
u StegFS, Pang, Tan, and Zhou
u DenFS, Gasti and others
![Page 8: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/8.jpg)
Previous Work on the Matter
u Anderson and others…
u StegFS, McDonald and Kuhn
u StegFS, Pang, Tan, and Zhou
u DenFS, Gasti and others
u Mobiflage, Skillen and Mannan
![Page 9: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/9.jpg)
Previous Work on the Matter
u Anderson and others…
u StegFS, McDonald and Kuhn
u StegFS, Pang, Tan, and Zhou
u DenFS, Gasti and others
u Mobiflage, Skillen and Mannan
u WhisperYAFFS
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Why is DEFY different?
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Main component of DEFY?
![Page 12: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/12.jpg)
Main component of DEFY?
YAFFS
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YAFFS (Yet Another Flash File System)
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YAFFS (Yet Another Flash File System)
u Read and Write at Page level, delete at Block level (NAND Flash Architecture)
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YAFFS (Yet Another Flash File System)
u Read and Write at Page level, delete at Block level (NAND Flash Architecture)
u Per-page Out Of Bounds (OOB) Area for MetaData (NAND Flash Architecture)
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YAFFS (Yet Another Flash File System)
u Read and Write at Page level, delete at Block level (NAND Flash Architecture)
u Per-page Out Of Bounds (OOB) Area for MetaData (NAND Flash Architecture)
u Dynamic Wear Leveling (NAND Flash Architecture)
![Page 17: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/17.jpg)
YAFFS (Yet Another Flash File System)
u Read and Write at Page level, delete at Block level (NAND Flash Architecture)
u Per-page Out Of Bounds (OOB) Area for MetaData (NAND Flash Architecture)
u Dynamic Wear Leveling (NAND Flash Architecture)
u Log Structured File System
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Design Requirements
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Design Requirements
u Deniability Levels
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Design Requirements
u Deniability Levels
u Secure Deletion
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Design Requirements
u Deniability Levels
u Secure Deletion
u Authentication Encryption
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Design Requirements
u Deniability Levels
u Secure Deletion
u Authentication Encryption
u Minimizing Data Loss
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Design Requirements
u Deniability Levels
u Secure Deletion
u Authentication Encryption
u Minimizing Data Loss
u Wear Leveling
![Page 24: DEFY: A Deniable, Encrypted File System for Log Structured ...webpages.eng.wayne.edu/~fy8421/17fa-csc6991/slides/10-DEFY.pdfMain component of DEFY? YAFFS . YAFFS (Yet Another Flash](https://reader034.vdocuments.us/reader034/viewer/2022050508/5fa4130e2c7d6e1e2452b3ef/html5/thumbnails/24.jpg)
Design Requirements
u Deniability Levels
u Secure Deletion
u Authentication Encryption
u Minimizing Data Loss
u Wear Leveling
u Easy Deployment
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Design Overview
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Design Overview – Deniability Levels
u Each level is associated with a Level Directory, which exists under the root directory.
u All files in each level are within its given directory.
u Each level has its own name and key, derived from user password
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Design Overview – Authentication Encryption
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Design Overview – Secure Deletion
u All or Nothing transform
u Single parts of ciphertext cannot be decrypted
u Only the entire cyphertext can be decrypted
u To achieve secure deletion, part of the ciphertext is deleted, making it impossible to get back the original data.
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Design Overview – Secure Deletion & Authentication Encryption
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OOD Area and MetaData
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OOD Area and MetaData
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Design Overview – Minimized Data Loss
u Any encrypted page will be viewed as free by the page allocator
u DENY uses 3 methods to mitigate this problem
1. When higher levels are revealed, all lower levels are as well
2. One level per block policy
3. DEFY writes checkpoints in a way the prevents overwriting of higher levels
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Design Overview – Minimized Data Loss
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Security Analysis
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Security Analysis
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Security Analysis
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Security Analysis
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Overhead
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Questions ?