Blockchain_Wallet

# Blockchain_Wallet  ## Multiwallet - Step by Step Guide --- #### Initial Requirements - New Startup Main Focus of a newly startup company is to build a portfolio management system (PMS) that supports both, traditional assets (gold, silver, stocks, etc.) and currently very hot topic - crypto-assets!! But as there are many coins, our task is to understand how HD wallets work, and to build a system that can create them. #### Race to capture the market `hd-wallet-derive` - A command line tool that supports BIP32, BIP39 and BIP44 and also supports non-standard derivation paths for the most popular wallets. Unfortunately, there arent many tools available in `python` and we need to integrate the script in backend with `python`. Once the integration is done with this "universal" wallet, one can manage billions of addresses across 300+ coins, giving a serious edge against the competition. ## Dependencies - PHP must be installed on operating system (any version, 5 or 7). No need to know any PHP - Clone the [`hd-wallet-derive`](https://github.com/dan-da/hd-wallet-derive) tool. - [`bit`](https://ofek.github.io/bit/) Python Bitcoin library. - [`web3.py`](https://github.com/ethereum/web3.py) Python Ethereum library. ## Instructions <details> <summary>Project setup</summary> - Create a project directory called `wallet` and `cd` into it. - Clone the `hd-wallet-derive` tool into this folder and install it using the instructions on its `README.md`. - Create a symlink called `derive` for the `hd-wallet-derive/hd-wallet-derive.php` script into the top level project directory like so: `ln -s hd-wallet-derive/hd-wallet-derive.php derive` This will clean up the command needed to run the script in the code, to call `./derive` instead of `./hd-wallet-derive/hd-wallet-derive.php.exe`. - Test run the `./derive` script properly, use one of the examples on the repo's `README.md` *Note*: If one gets an error running `./derive`, as it happens in Windows machine then use: `./hd-wallet-derive/hd-wallet-derive.php.exe` - Create a file called `wallet.py` -- universal wallet script. Directory tree for `hd-wallet-derive`  </details> <details> <summary>Setup constants</summary> - In a separate file, `constants.py`, set the following constants: - `BTC = 'btc'` - `ETH = 'eth'` - `BTCTEST = 'btc-test'` - In `wallet.py`, import all constants: `from constants import *` - Use these anytime to reference these strings, both in function calls, and in setting object keys. </details> <details> <summary>Generate a Mnemonic</summary> - Generate a new 12 word mnemonic using `hd-wallet-derive` or by using [this tool](https://iancoleman.io/bip39/). - Set this mnemonic as an environment variable, and include the one generated as a fallback using: `mnemonic = os.getenv('MNEMONIC', 'insert mnemonic here')` </details> <details> <summary>Deriving the wallet keys</summary> - Use the `subprocess` library to call the `./derive` script from Python. Make sure to properly wait for the process. - The following flags must be passed into the shell command as variables: - Mnemonic (`--mnemonic`) must be set from an environment variable, or default to a test mnemonic - Coin (`--coin`) - Numderive (`--numderive`) to set number of child keys generated - Set the `--format=json` flag, then parse the output into a JSON object using `json.loads(output)` - Wrap all of this into one function, called `derive_wallets` - Create an object called `coins` that derives `ETH` and `BTCTEST` wallets with this function. When done properly, the final object should look something like this (there are only 3 children each in this image):  Test the `coins` by calling `coins[COINTYPE][INDEX]['privkey']`. </details> <details> <summary>Linking the transaction signing libraries</summary> Use `bit` and `web3.py` to leverage the keys obtained in the `coins` object. Create 3 more funtions: 1. `priv_key_to_account` -- this will convert the `privkey` string in a child key to an account object that `bit` or `web3.py` can use to transact. This function needs the following parameters: - `coin` -- the coin type (defined in `constants.py`). - `priv_key` -- the `privkey` string will be passed through here. Check the coin, then return one of the following functions based on the library: - For `ETH`, return `Account.privateKeyToAccount(priv_key)` - For `BTCTEST`, return `PrivateKeyTestnet(priv_key)` 2. `create_tx` -- this will create the raw, unsigned transaction that contains all metadata needed to transact. This function needs the following parameters: - `coin` -- the coin type (defined in `constants.py`). - `account` -- the account object from `priv_key_to_account`. - `to` -- the recipient address. - `amount` -- the amount of the coin to send. Check the coin, then return one of the following functions based on the library: - For `ETH`, return an object containing `to`, `from`, `value`, `gas`, `gasPrice`, `nonce`, and `chainID`. Make sure to calculate all of these values properly using `web3.py`! - For `BTCTEST`, return `PrivateKeyTestnet.prepare_transaction(account.address, [(to, amount, BTC)])` 3. `send_tx` -- this will call `create_tx`, sign the transaction, then send it to the designated network. This function needs the following parameters: - `coin` -- the coin type (defined in `constants.py`). - `account` -- the account object from `priv_key_to_account`. - `to` -- the recipient address. - `amount` -- the amount of the coin to send. Check the coin, then create a `raw_tx` object by calling `create_tx`. Then, sign the `raw_tx` using `bit` or `web3.py` (hint: the account objects have a sign transaction function within). Once signed the transaction, send it to the designated blockchain network. - For `ETH`, return `w3.eth.sendRawTransaction(signed.rawTransaction)` - For `BTCTEST`, return `NetworkAPI.broadcast_tx_testnet(signed)` </details> <details> <summary>Execute the transactions</summary> ***Bitcoin Testnet transaction*** - Fund a `BTCTEST` address using [this testnet faucet](https://testnet-faucet.mempool.co/). - Use a [block explorer](https://tbtc.bitaps.com/) to watch transactions on the address. ***BTCTEST Transaction*** `btc_test_acc = priv_key_to_account(BTCTEST,btc_test_PrivateKey)` `create_tx(BTCTEST,btc_test_acc,"n1u1MQ11bBZvj6JzjzJKxiT5PgCsfc3ZiQ", 0.01)` `send_txn(BTCTEST,btc_test_acc,"n1u1MQ11bBZvj6JzjzJKxiT5PgCsfc3ZiQ", 0.01)` Confirmation on executed transaction  ***ETH Transaction - Local PoA*** - Add one of the `ETH` addresses to the pre-allocated accounts in `mtestnet.json` - Initialize using `geth --datadir nodeX init mtestnet.json`. - [Add the following middleware](https://web3py.readthedocs.io/en/stable/middleware.html#geth-style-proof-of-authority) to `web3.py` to support the PoA algorithm: `from web3.middleware import geth_poa_middleware w3.middleware_onion.inject(geth_poa_middleware, layer=0)` - Connect to HTTP with address private key `w3 = Web3(Web3.HTTPProvider("http://127.0.0.1:8545"))` - Due to a bug in `web3.py`, send a transaction or two with MyCrypto first, since the `w3.eth.generateGasPrice()` function does not work with an empty chain. Use one of the `ETH` address `privkey`, or one of the `node` keystore files. - Send a transaction from the pre-funded address within the wallet to another, then get the `TxStatus` from MyCrypto `