Noding a Blockchain

Blockchains and cryptocurrency are all the hot rage these days. But if you're like me, it all seems like a bunch of voodoo magic math and super complicated algorithms.

So I decided the best way to de-mystify and learn it was to build my own blockchain and cryptocurrency. And of course, I started with Node! I'm going to walk you through some of my code and show a few bits of intermediate-to-advanced Node that I had to tackle to build my blockchain.

Topics covered will include: efficient asynchronous logic, SHA256 hashing and RSA cryptography, mesh communications via UDP and TCP messages, streams, offloading work to child processes, and persisting data in Git.

Transcript

1. NODING A BLOCKCHAIN
   KYLE SIMPSON GETIFY@GMAIL.COM
   

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2. Private Databases
   

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4. • Read/write access is private
   • Data is (usually) mutated
   • Sharing and backups:

   replication
   • All stakeholders are trusted
   

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5. • Private/sensitive data
   • "Single" point of failure (SPOF)
   • Target for hacking
   • Load balancing, eventual

   consistency
   

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6. Public Databases
   

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8. • Read/write access is public
   • Data is never mutated
   • No stakeholders are trusted
   

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9. • Public data
   • Trust based on math
   • Essentially zero failure
   • "50% + 1" weakness
   • Never consistent, consensus

   complications
   

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10. What is a blockchain?
    

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11. 0
    1
    2
    3
    A chain of blocks.
    

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12. 0
    1
    B22D1D8...89E2B87
    BCC29FC...E03F7E0
    B22D1D8...89E2B87
    

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13. 0
    1
    B22D1D8...89E2B87
    {
    index: 1,
    hash: "BCC29FC...E03F7E0,
    prevHash: "B22D1D8...89E2B87",
    data: ... ,
    timestamp: 1524029051480,
    }
    

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14. {
    index: 1,
    prevHash: "B22D1D8...89E2B87",
    data: ... ,
    timestamp: 1524029051480,
    }
    SHA256(
    );
    // "BCC29FC...E03F7E0"
    MATH!
    

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15. 0
    1
    B22D1D8...89E2B87
    BCC29FC...E03F7E0
    B22D1D8...89E2B87
    

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16. {
    index: 1,
    prevHash: "B22D1D8...89E2B87",
    data: ... ,
    timestamp: 1524029051480,
    }
    

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17. {
    index: 1,
    prevHash: "B22D1D8...89E2B87",
    data: ... ,
    timestamp: 1524029051480,
    }
    data: [
    { hash: "C37AF10...0040A18", data: ... , timestamp: ... , ... },
    { hash: "B9DC4FC...91F59BD", data: ... , timestamp: ... , ... },
    ... ,
    ],
    {
    index: 1,
    prevHash: "B22D1D8...89E2B87",
    timestamp: 1524029051480,
    }
    

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18. Timestamps
    In blockchains, purely
    informational
    

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19. Code!
    

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25. Hashes
    

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26. Rewrite history?
    Recompute All Hashes!
    

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27. Chaos
    

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28. Make recomputation of all
    hashes in the whole chain
    "hard"!
    (aka "not worth it")
    

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29. Consensus
    50% + 1
    

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30. Proof of Work
    Proof of Stake
    ...
    

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31. "Hard" math problem
    Solution: brute force
    "Mining"
    

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33. Transactions
    

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34. Authorization
    

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35. Private
    Key
    Public

    Key
    Asymmetric Cryptography
    

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36. Private
    Key
    Public

    Key
    Asymmetric Cryptography
    

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37. Private
    Key
    Public

    Key
    "some secret text"
    Encrypt
    Decrypt
    "some secret text"
    "jn4ra...bBH3/sKn"
    What I always thought...
    

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38. Private
    Key
    Public

    Key
    "some secret text"
    Encrypt
    Decrypt
    "some secret text"
    "jn4ra...bBH3/sKn"
    How it actually works...
    

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39. Public

    Key
    Private
    Key
    "some public text"
    Sign
    Verify
    "c7/De0...fhJjK3"
    Digital Signatures
    ✓
    

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42. Node Code!
    

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46. github.com/getify/CAF
    

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51. NODING A BLOCKCHAIN
    KYLE SIMPSON GETIFY@GMAIL.COM
    THANKS!!!!
    

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