Attaining data security in cloud computing


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This is my presentation which gives security for the data to be stored in cloud storage. The security is obtained through Cryptography (encryption and decryption) and the tools used in this paper is DOT NET and Gladinet.

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Attaining data security in cloud computing

  1. 1. Attaining Data Security in Cloud Computing Submitted by M.Gopinath (1074305) VLSI DESIGN Under the Guidelines of Dr.V.Sumathy
  2. 2. Objective • To address the security problems such as insider attacks and identity theft. • To store the data across network-distributed systems in a secure way.
  3. 3. Challenging Security Threats • Loss of control over data in cloud storage • Traditional integrity menace Due to dynamic data update Due to storing data redundantly in various physical location • Insider attack
  4. 4. Literature Survey • Great amount of data widely spread over the network require adequate management, to ensure authorization, confidentiality and integrity. • Based on the cryptography and the nature of the cloud, information security has to be achieved.
  5. 5. Cloud Computing • Computing on multiple server via a digital network • A model for enabling convenient, ondemand network access to a shared pool of configurable computing resources • Technique which moves the application software and databases to the large data centers
  6. 6. Cloud Computing contd.. • Provides computation, software, data access, and storage services • Does not require end-user’s knowledge of the physical location and configuration of the system that delivers the services
  7. 7. Technologies in Cloud • • • • • Grid computing Virtualization Infrastructure-as-a-Service Software-as-a-Service Utility Computing
  8. 8. Cloud Storage • A model of networked online storage where data • • is stored on multiple virtual servers, generally hosted by third parties, rather than being hosted on dedicated servers. Companies do not need to install physical storage devices in their own datacenter or offices, which reduces IT and hosting costs. Companies need to pay only for the storage they actually use.
  9. 9. Benefits of Cloud • • • • Highly scalable Highly available Dynamically allocated resources Pay only for resources that you use
  10. 10. System Model Users (consists of both consumers and organizations), who have data to be stored in the cloud Cloud Service Provider(CSP), who has resources and expertise in building and managing distributed cloud storage servers Third Party Auditor(TPA), who has expertise and capabilities that users may not have, to assess and expose risk of cloud storage
  11. 11. Adversary model • It tries to compromise a number of cloud data storage servers and is able to modify or delete users’ data. • Two types of adversary with different levels of capability Weak adversary Strong adversary
  12. 12. Data Storage Security • Encryption – the process of transforming plaintext into ciphertext using cipher • Decryption – the reverse process of encryption • Digital Signature
  13. 13. Cipher Types • Symmetric cryptography • Asymmetric or Public Key cryptography
  14. 14. Symmetric Cipher
  15. 15. DES The Data Encryption Standard (DES) is a symmetric-key block cipher published by the National Institute of Standards and Technology (NIST).
  16. 16. General Structure of DES
  17. 17. DES uses 16 rounds. Each round of DES is a Feistel cipher.
  18. 18. Key Generation
  19. 19. Properties of DES • Avalanche effect • completeness Design Criteria • S-boxes • P-boxes • Number of rounds
  20. 20. Public Key Cipher
  21. 21. RSA Algorithm • An algorithm for public-key (asymmetric) • • • • cryptography. Based on the presumed difficulty of factoring large integers, the factoring problem. RSA involves a public key and private key. Anyone can use the public key to encrypt a message. If the public key is large enough, only someone with knowledge of the prime factors can feasibly decode the message.
  22. 22. Key Generation • • • • • • Choose two distinct prime numbers p and q. Compute n = pq. Compute φ(n) = (p – 1)(q – 1), where φ is Euler's totient function. Choose an integer e such that 1 < e < φ(n) and gcd(e,φ(n)) = 1, i.e. e and φ(n) are coprime. Determine d = e–1 mod φ(n); i.e. d is the multiplicative inverse of e mod φ(n). The public key pair is {e,n} and the private key pair is {d,n}.
  23. 23. ENCRYPTION For sending message to B: • Obtains the recipient B's public key (n, e). • Represents the plaintext message as a positive integer m, 1 < m < n. • Computes the ciphertext C = me mod n. • Sends the ciphertext C to B.
  24. 24. DECRYPTION Sender decrypts the message as follows: • Uses his private key (n, d) to compute m = Cd mod n. • Extracts the plaintext from the message representative m.
  25. 25. Features of RSA • Secrecy and Privacy • Integrity • Authentication • Non-repudiation
  26. 26. Proposed Algorithm • Public-Key encryption • • – increased security – Convenience Secret-Key encryption – Speed Best solution is to combine public- and secret-key cryptography to get both security and speed
  27. 27. Proposed Algorithm contd. • User logins must be used to provide authorization. • The symmetric Data Key K is used for data encryption. • Then the symmetric key K is encrypted through the user public key KPUB, and it is written in the distributed storage system.
  28. 28. Simulation Tools • Dot Net framework • Gladinet Cloud Desktop • Amazon Cloud Drive • and OpenBox platform
  29. 29. Reference • Gary C.Kessler, 1998, “An Overview of Cryptography”, • • • • • • Chapter 3. William Stallings, “Cryptography and Network Security”, Fourth Edition, Chapters 3, 5, 9 and 13., “Amazon Web Services (AWS),” Online at, 2008.
  30. 30. Thank you