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Blockchain for dummies

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Blockchain for dummies

  1. 1. Blockchain for dummies or how to make $127 million in 20 minutes… Thibault Debatty Cyber Defense Lab, Royal Military Academy www.cylab.be BeMilCIS2019
  2. 2. Like GO : simple principle, complex implications! Blockchain for dummies - BeMilCIS2019 2
  3. 3. Blockchain 3Blockchain for dummies - BeMilCIS2019
  4. 4. Blockchain Each block contains •A link to previous block (the chain) •A timestamp •Data •A hard to compute hash 4Blockchain for dummies - BeMilCIS2019
  5. 5. Miners •Keep a copy of the complete chain (BTC: 160GB) •Create (and solve) new blocks… •… starting from the end of the chain •Broadcast the new block to other miners 5Blockchain for dummies - BeMilCIS2019
  6. 6. Branching •Can happen •Will solve automatically 6Blockchain for dummies - BeMilCIS2019
  7. 7. Branching Blockchain for dummies - BeMilCIS2019 7
  8. 8. Branching Blockchain for dummies - BeMilCIS2019 8
  9. 9. Blockchain tampering Modifying the past requires •To create a new branch •And to overtake the main branch 9Blockchain for dummies - BeMilCIS2019
  10. 10. Blockchain tampering Blockchain for dummies - BeMilCIS2019 10
  11. 11. Blockchain •A replicated database •That records time related data •With eventual consistency •Protects integrity (non-repudiation): • With no central authority • Even with untrusted participants 11Blockchain for dummies - BeMilCIS2019
  12. 12. But why so much hype? Blockchain for dummies - BeMilCIS2019 12
  13. 13. Bitcoin 13Blockchain for dummies - BeMilCIS2019
  14. 14. Bitcoin Data of a block is a list of transactions •E.g. 0,01 BTC from A to B Difficulty adapts : 1 new block every 10 minutes Transaction considered as final after 6 blocks (1h) 14Blockchain for dummies - BeMilCIS2019
  15. 15. Bitcoin Uses asymetric cryptography •Private key used to sign transactions •Public key is the address of account Blockchain for dummies - BeMilCIS2019 15
  16. 16. Bitcoin wallet •Stores public and private keys •Create and sign transactions •Send transaction to miners •Can be online, desktop, app 16Blockchain for dummies - BeMilCIS2019
  17. 17. Online wallets 17Blockchain for dummies - BeMilCIS2019
  18. 18. Online wallets As safe as the website https://www.theregister.co.uk/2019/06/07/komodo_npm_wallets/ 18Blockchain for dummies - BeMilCIS2019
  19. 19. Desktop wallets and apps 19Blockchain for dummies - BeMilCIS2019
  20. 20. Desktop wallets and apps 20Blockchain for dummies - BeMilCIS2019
  21. 21. 21Blockchain for dummies - BeMilCIS2019 Miners consume a LOT of power (5MW)
  22. 22. How do miners make money? •Controlled supply: • 12,5 new reward bitcoins per block • (originally 50) •Transaction fee: • $2/transaction on average • $8000/block But what when reward bitcoins disappear? 22Blockchain for dummies - BeMilCIS2019
  23. 23. How can youget BTC? •Mine •Buy •As a payment 23Blockchain for dummies - BeMilCIS2019
  24. 24. What makes the value of BTC? Just like gold : •Supply and demand •Mining cost Blockchain for dummies - BeMilCIS2019 24
  25. 25. Other (useful) applications of Blockchain? Blockchain for dummies - BeMilCIS2019 25
  26. 26. obvious: cryptocurrencies Currently 26 active cryptocurrencies! •Ethereum (ETH) •Bitcoin Cash (BCH) •Ripple (XRP) Totalling more than $100bn Blockchain for dummies - BeMilCIS2019 26
  27. 27. possible: smart contracts Record transactions with no central authority •Finance and trade (e.g. real estate) •Authorship •NATO NCIA : contracts handling Blockchain for dummies - BeMilCIS2019 27
  28. 28. possible: smart contracts Replace DNS authorities and SSL/TLS certificate authorities •Blockchain DNS •okTurtles DNSChain But what about proof of work, reward and price? Blockchain for dummies - BeMilCIS2019 28
  29. 29. Doubtful… •US DoD messaging system •Health records management Why not a centralized system? Blockchain for dummies - BeMilCIS2019 29
  30. 30. In conclusion, Blockchain •Is a simple chain of blocks •Offers integrity protection in a network with no central authority •Has a cost in time and power Blockchain for dummies - BeMilCIS2019 30
  31. 31. Thank you! Find this presentation and more resources at www.cylab.be Blockchain for dummies - BeMilCIS2019 31

Editor's Notes

  • 10 x 12 x 30 miners
    each 10 Thash/sec, 1500W, 3blocks/year
    1block/day/column
    Maison monophasé: 8kw : 5 miners

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