Data Integrity proofs in cloud storage
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This document discusses cloud computing and proposes a scheme for proof of data integrity in the cloud. It begins by defining cloud computing and describing the infrastructure needed to run applications over the internet. It then discusses security issues with cloud storage, where users do not have control over remotely stored data. The proposed scheme generates encrypted metadata for files and allows users to verify integrity by challenging the data center to provide specific bits, proving the file was not illegally modified. The scheme is best suited for encrypted static files stored in the cloud.
Data Integrity proofs in cloud storage
- 4. Applications and services that run on a distributed network using virtualized resources and accessed by common internet protocols and network standards Cloud Computing is a paradigm in which information is permanently stored in servers on the internet and can be accessed from anywhere
- 6. Data center Office space Servers and storages Team of technical personnel's Coolants Network Power
- 7. Provides all the infrastructure needed to run applications over the internet Increased storage Reduced cost Flexibility Increased mobility Highly automated
- 8. -> Sometimes referred to as "on-demand software" is a software delivery model in which software and its associated data are hosted centrally and are typically accessed by users
- 9. • ….enables you to create web applications quickly, without the • cost and complexity of buying and managing the underlying software or hardware… No Frequent updates Inexpensive
- 11. Data Integrity and Data Privacy Availability and Reliability Bandwidth and Latency guarantees Portability and Compliance
- 12. Cloud storage moves the user’s data to large data centers, which are remotely located, on which the user does not have any control However there are lot of security issues which need to be considered Data integrity Authentication Small devices like PDA’s, mobiles, and laptops are associated with limited battery power and computation speed
- 13. We provide a scheme which gives a proof of data integrity in the cloud through which the user can verify the correctness of his data, this proof can be termed as Proof of Retrievability (POR) This enables individual to entertain Economic advantages Zero Maintenance Note: -> Our scheme just checks the integrity (if the data is illegally modified) only of static data…
- 14. This proof can be agreed upon by both the cloud and the customer and can be incorporated in SLA. SLA is part of service contract where the level of services being offered is formally defined.
- 15. Key generator: A random key is generated Encryption: A metadata of the file is generated and is encrypted using any suitable algorithm Archive: It is the data center where the data is outsourced Challenge: Verification of data integrity by the user… Response: Proof of data integrity by data center
- 16. A simplest Proof of Retrievability can be made using hash key function File (F) Data Center (archive) Cryptographic Hash Function Hk(F) User DB Hash Secret key (k) Encrypted file(~f) StoredRetrieves C H A L L E N G E Response
- 17. • Computing hash value for moderately large file might be overhead for some device like Mobiles, PDA’s and Laptops • For each verification request from client the archive has to process the entire file • High resource cost and lot of ambiguity as a result of maintaining secret key and number of hash keys….
- 18. Proposed a theory to proof the retrievability for large files using sentinels…. According to them 1 2 3 4 5 6 7 Data File( f ) s s s s s s s s s s s s s s s s s s s s s Data file with seven blocks Inserting sentinels at different positions and noting their position, present at different blocks File(~f) Encryption (~F ) Data Archive To hide the position of sentinels
- 19. Computationally burdensome for entire file to be encrypted for small devices This scheme is best suited for encrypted files Data Center Cloud Storage Client
- 20. In this we provide a scheme of data integrity , which the customer can utilize to check the correctness of his data by including SLA
- 21. M bits M bits M bits M bits M bits M bits File (F) with n blocks, and each block of size M bits K bits K<<<M, K bit positions are noted Where K is user defined E M1 K bits E M2 K bits E M3 K bits E M4 K bits E M5 K bits E M6 Metadata Encrypting k bits using any appropriate algorithm Generation of individual metadata
- 22. File (F) Metadata Data Center File is appended with metadata New file (~F) is stored at data center Client challenges by specifying (ith) block of file and the jth bit of i Response and challenge should be same to accept the file
- 25. Our scheme is only for static data Developing for dynamic data will be a future challenge