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DEFY: A Deniable, Encrypted File System for Log Structured Storage
WRITTEN BY: PRESENTED BY: TIMOTHY PETERS NICHOLAS BURTON MARK GONDREE ZACHARY PETERSON
DEFY: A Deniable, Encrypted File System for Log Structured Storage - - PowerPoint PPT Presentation
DEFY: A Deniable, Encrypted File System for Log Structured Storage - - PowerPoint PPT Presentation
DEFY: A Deniable, Encrypted File System for Log Structured Storage WRITTEN BY: PRESENTED BY: TIMOTHY PETERS NICHOLAS BURTON MARK GONDREE ZACHARY PETERSON What is encryption? Why hide encryption? Previous Work on the Matter u Anderson and
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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
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Previous Work on the Matter
u Anderson and others… u StegFS, McDonald and Kuhn u StegFS, Pang, Tan, and Zhou
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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
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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
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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?
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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)
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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) 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
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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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