Setup

Install

• docker-compose run node1 composer install install PHP dependencies
• docker-compose run node1 yarn install install Node + JS dependencies
• docker-compose run node1 yarn dev compile browser-fliendly JS and CSS via webpack
• docker-compose up -d to bring the conteiners online
• docker-compose run node1 php artisan migrate:fresh ; docker-compose run node1 php artisan db:seed
• docker-compose run node2 php artisan migrate:fresh ; docker-compose run node2 php artisan db:seed

Link nodes together

• docker-compose exec node1 php artisan node:bootstrap
• docker-compose exec node2 php artisan node:bootstrap

Unlink nodes

• docker-compose exec node1 php artisan node:unlink
• docker-compose exec node2 php artisan node:unlink

Add more miners

• docker-compose scale miner1=5 miner2=5

Presentation

http://github.com/sash/blockchain-network-example

Bobby_Borisov & alexiev

Core mechanics of the project

• No transactions are lost during conflict resolution
• Balance is kept in an optimized database for quick balance checks
• Wallet is HD and transactions are made (if necessary) from several addresses in order to match the requested send
• Wallet shows as recipient address the first address that was never spent from (the signature was never revealed)
• Wallet and explorer are implemented in react (client-side apps) and consume the APIs of the node
• The explorer is a clone of blockhain.info
• The faucet is implemented in pure php (no time for react on that!)
• Faucet requests are queued and done one at a time once a minute
• The faucet has no spam prevention but there should be at least CAPTCHA (in real life)!
• Miners are implemented in nodejs
• Miners are mulithreaded
• Miners are now limited to 1hash per second per thread (we run on battery)
• Unit tests
• The setup: 1 chain explorer, 2 faucets, 1 hd wallet, 2 nodes with one miner each. the miners mine for the faucets
• Docker is used to manage the services. We can easily ramp-up the computing power of the miner by launching more miners docker-compose scale miner1=10 miner2=10

Scenario: Business as usual

0. Initialize and link the nodes
1. Make a new wallet http://localhost:5003
2. Fund the wallet via the faucet (docker-compose faucet1_cron exec php artisan faucet:drip)
3. Create another wallet (separate browser)
4. Send money to the other address. Wait for confirmation
5. Check both notes are the same (blockwise and transactionwise)

Scenario: Double spend attempt + Conflict resolution

0. Continue the example from above
1. Faucet 1 coin to your wallet, wait for confirmation
2. Unlink the nodes docker-compose exec node1 php artisan node:unlink; docker-compose exec node1 php artisan node:unlink
3. Using node1 spend the token back to the faucet. Using node2 do the same. (use less then one coin so there is enough funds for the fee)
4. Wait for the transaction to validate ON BOTH NODES. Take a look at the block explorer on both nodes
5. Link the nodes back together docker-compose exec node1 php artisan node:bootstrap
6. Watch the conflict resolve itself via the block explorer

Scenario: Delayed spend example - no transaction was lost

0. Continue the example from above
1. Fund the wallet with another token, so the transaction that was declared invalid is now possible
2. Watch the lingering transaction get confirmed

Initial funds owners (each has 10kFs in the genesis)

The first two are used by the faucets

Address	Private Key
be9c053812ca0cf8ae40aab3047f1b17e586765d	0f9d3070204642bc8eb07b00a99ef38eebfec965733a3f70548ce99484fdfd99
c06e8b1d745f50658be0a6e4bd6b01c94878a923	e5fcb644cb5ff2a34d8d479b2fc775c6e4f242ebd8f4eb146bf3985d968c67a5
9a0bc19436ff653a7c631edc82451a684bccbbb2	1827f2551a5e6c64f4a601c569c3a092c8a1dd770246947ecc8d6f01b29db2db
b379a0f6378b612a46a346e8136ba3b9fb324218	b3cf4c12b7e41b138ce19af734e7f3856a58858ca1430fb0f0c086b4f644c476
626b5ce05e2b40812cf283fc45434e799f036d9c	05770798da086eab3d7e665e883d62003018d02f4021d2b9598f3ff9e11b2cc0
f86d8b68d81bd1bb2637e4874c31c1d5bd3a0169	98acc7b63049233d873c2dda03c7c29ead53a816ef463225dd9d72da9d69c884
b0238c61a3bfe54bd7ae95aeaea25a3a942759e4	906bad6aa7fc42f38c3dc6bc51729e645fe3b8b1221323ffe35e4fa1029792f8
a163ad1c02203518eeae23f6348d8c1dc00dac25	e3c2b302c54725f3f6029ed6829e7b9f8c1a1e4aff5c4ced054cf16cef7f311d
6b2bc3ffcda1f096a3ac08fa38352505f57e543e	42367b96408ddb7c5f5d79163add487dde661ad474085b662bbddf6edebe92ec
004ca2dd10fcf53ad30631e7d323aa80c9ecf317	600fea4a214cadb607e34ed0bb091297864cc12162f1e6d6f67a4c5efac06e05

Homeworks (By Alex)

Docker + Docker compose are required in order to build the dev environment. To install docker go to https://www.docker.com/get-docker

• run docker-compose run node1 composer install to setup PHP dependencies
• run docker-compose up -d to bring the conteiners online
• run docker-compose exec node1 php artisan to see available solutions (they are in the blockchain namespace). Run the examples using docker-compose exec app php artisan blockchain:[example-name]

blockchain
  blockchain:ecc        Exercises: Blockchain Cryptography. 5.  Ethereum Signature Creator, 6.  Ethereum Signature to Address, 7.  Ethereum Signature Verifier
  blockchain:ethereum   Exercises sign verify ethereum message
  blockchain:hash       Exercises: Blockchain Cryptography. 1) Calculate Hashes
  blockchain:hmac       Exercises: Blockchain Cryptography. 2) Calculate HMAC
  blockchain:scrypt     Exercises: Blockchain Cryptography. 3) Derive Key by Password using SCrypt
  blockchain:symmetric  Exercises: Blockchain Cryptography. 4) Symmetric Encryption / Decryption (AES + SCrypt + HMAC)

• run docker-compose exec node1 yarn install to setup node dependencies
• Exercises: Blockchain Cryptography 8. Bitcoin Address Generator (C# Edition) is in c#/BitcoinAddressGenerator.cs
• Exercises: Blockchain Cryptography 9. Bitcoin Address Generator (JS Edition) is in docker-compose exec app node node/bitcoin-address-generator.js
• Exercises: Blockchain Cryptography 10. Private Key to Bitcoin Address is in docker-compose exec app node node/private-key-to-bitcoin-address.js
• Exercises: Blockchain Cryptography 11. Asymmetric Encryption / Decryption is in docker-compose exec app node node/asymmetric-encryption-decryption.js

Homework for Lecture 5 (Consensus Algorithms)

• docker-compose exec app php artisan blockchain:private-to-address
• "Exercises: Sign and Verify Transaction in JavaScript" is in docker-compose exec app node node/sign-and-verify-transactions.js

License

The Laravel framework is open-sourced software licensed under the MIT license. The rest of the code is also licensed under MIT license