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Blockchain

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Blockchain technology

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Blockchain

  1. 1. Blockchain Technologies BABU PALLAM 2017CS18 M.tech, 2nd Year, Computer Science and Engineering(CSED) Motilal Nehru National Institute of Technology Allahabad October 15, 2018
  2. 2. Contents 1 Introduction What is blockchain? Why do we need blockchain? 2 Blockchain fundamentals Architecture How blockchain works? 3 Blockchain underlying technologies 4 Case Study: BIDaaS 5 Conclusion BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 2 / 22
  3. 3. What is blockchain ? It is a distributed ledger technology, developed by Satoshi Nakamoto, in 2008, through the invention of Bitcoin. Different perspectives: It is a data structure. It is an abstract data type. It is a technology. It is an umbrella term. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 3 / 22
  4. 4. Why do we need blockchain? A new social adequate is being created! Centralization to decentralization. Untrusted environment require documentation. Characteristics of blockchain: It is immutable. It provides security and resilient towards tampering. It is always consistent. It provides decentralized computing platform. It provides cent per cent uptime of data. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 4 / 22
  5. 5. Blockchain Architecture Communication medium: Internet. Decentralised network: Peer to peer network. Decentralised storage: Distributed ledger. Decentralised law: Consensus algorithms. Decentralised apps.: Interface between the user. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 5 / 22
  6. 6. How blockchain works? Tasks need to be addressed: 1 Transaction generation 2 Storing the transactions 3 Preparing trustworthy environment 4 Distributing blocks and transactions 5 Updating ledger by new transactions or blocks BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 6 / 22
  7. 7. How blockchain works? 1 Transaction generation Signing the transaction At sender(A) side: BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 7 / 22
  8. 8. How blockchain works? 1 Transaction generation Verifying the transaction At recipient side: BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 8 / 22
  9. 9. How blockchain works? 2 Storing the transactions BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 9 / 22
  10. 10. How blockchain works? 3 Preparing trustworthy environment Goal: Blockchain should be immutable. Idea: Consensus is computationally expensive. Merkle tree makes manipulation easily noticable. 4 Distributing blocks and transactions Goal: How do the nodes observe new transactions and blocks? Idea: Messages send in a gossip style. Timestamp in each transaction helps node to order and ignore duplicates. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 10 / 22
  11. 11. How blockchain works? Concensus algorithm: Proof of work 1 Get the Merkle root from tree of transactions to be added. 2 Create previous hash reference. 3 set difficulty-level = number of zeros preceded by the hash. 4 Get timestamp. 5 Set nonce = 0. 6 Apply hash puzzle: Find the hash of block header by varying nonce, so that number of zeros at the first place of hash should be equal to difficulty-level. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 11 / 22
  12. 12. How blockchain works? 5 Updating ledger by new transactions or blocks 1 Node takes new transaction/block from mailbox and start processing. 2 In case of new transactions: 1 The node will verify each transaction. 2 If its invalid, node will discard it. 3 Perform proof of work with valid transactions 4 Broadcasts newly created block to the network. 3 In case of new blocks: 1 Verify all the transactions includes in it and proof of work. 2 Once it verified and is valid, update the local ledger 3 Once it verified and is invalid, discard it. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 12 / 22
  13. 13. Blockchain underlying technologies BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 13 / 22
  14. 14. Blockchain underlying technologies 1. Encryption Encryption: A way to acheive data security. Encryption in blockchain: Provides data security. Independent existence: Anywhere in digital world. Blockchain without Encryption: loss data security. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 13 / 22
  15. 15. Blockchain underlying technologies 1. Encryption Encryption: A way to acheive data security. Encryption in blockchain: Provides data security. Independent existence: Anywhere in digital world. Blockchain without Encryption: loss data security. 2. Smart contract Smart contract: Self exicuting script. Smart contract in blockchain: Helps to create business logic. Independent existence: Can be implemented. Blockchain without Smart contract: Possible. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 13 / 22
  16. 16. Blockchain underlying technologies 3. Distributed ledger Distributed ledger: A consensually shared and synchronized database across a network. Distributed ledger in blockchain: Ensures data consistency. Independent existence: Yes, possible. Phase King algorithm for BFT. Distributed lock service by google. Blockchain without distributed ledger: Possible, it is not mandatory. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 14 / 22
  17. 17. Case Study: Blockchain based ID as a Service BIDaaS Infrastructure BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 15 / 22
  18. 18. Case Study: Blockchain based ID as a Service The terms associated with the entities: Virtual ID of user Uusr Private key of User Kusr pri Public key of User Kusr pub Private key of Partner Kptn pri Public key of Partner Kptn pub Private key of BIDaaS provider Kpro pri Public key of BIDaaS provider Kpro pub Encryption with private key EKpri () Decryption with public key DKpub () nonce r BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 16 / 22
  19. 19. Case Study: Blockchain based ID as a Service User virtual ID creation: User generates the virtual ID from its private key Uusr = SHA256(Kusr pri ) User Registration: (Kusr pub, Uusr , EKpro pri (Kusr pub, Uusr )) BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 17 / 22
  20. 20. Case Study: Blockchain based ID as a Service Mutual authentication: User sends its virtual id and a nonce value to the associated partner. M1 = (Uusr , r, EKusr pri (Uusr , r)) The partner validates M1: DKusr pub (EKusr pri (Uusr , r)) The provider sends response message M2 back to the user. M2 = (Uusr , r + 1, EKusr pub (Uusr , r + 1, Kptn pub)) User validates M2 using r + 1. After validation, the user sends M3 as acknowledgement. M3 = (Uusr , r + 2, EKptn pub (Uusr , r + 2)) The partner validates M3, then mutual authentication is successful. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 18 / 22
  21. 21. Case Study: Blockchain based ID as a Service Real world example with BIDaaS infrastructure: BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 19 / 22
  22. 22. Conclusion Blockchain is unlocked a new paradigm for distributed computing and applications. The underlying technologies and new innovations make the blockchain revolution without blockchain. The future of blockchain would probably be a decentralized Internet, in turn a decentralized society. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 20 / 22
  23. 23. References By Hanna Halaburda Blockchain Revolution Without the Blockchain? Communications of the ACM, July 2018, Vol. 61 No. 7, Pages 27-29 10.1145/3225619. Johg-Hyouk Lee BIDaaS: Blockchain Based ID As a Service IEEE Access ( Volume: 6 ) 2169-3536 10.1109/ACCESS.2017.2782733. By Satoshi Nakamoto Bitcoin: A Peer-to-Peer Electronic Cash System www.bitcoin.org. BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 21 / 22
  24. 24. Thank You BABU PALLAM 2017CS18 (MNNIT) Blockchain Technologies October 15, 2018 22 / 22

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