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I'm not posing as an expert in consensus protocols. I agree with @mdigi14 that an incentive for the network to attack itself looks like a problem. Measuremnent strikes me as challenge. the longer they have been connected According to whom? This has to be measured, somehow, and the result might differ based on perspective since network connections ...


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Looking into it quickly I noticed you did not import the library Address and this is probably why your using Address as address doesn't work. Hope this helps.


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why the user should hash the transaction before he sends it? A transaction is a data structure just like a .json file. Therefore if senders wouldn't hash this data structure, it could become inconsistent, e.g. sometimes having more fields, sometimes not. Hashing it before, turns data to a consistent shape, resulting ALWAYS in hexadecimal of x bit (depending ...


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event definitions and emit steps are the go-to contract design step to be courtious to external clients using event listeners. Similar to subscribing to a feed and they can listen to specific contracts and topics, apply filters and so on. An entity that is not a node This is sort of a challenge. If they don't have their own then they will rely on ...


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Yes this is possible. The smart contract needs to emit events which are written to logs. Your entities outside the blockchain can read these logs from the blockchain nodes.


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The above section of the SQL query represents transaction fees that are incurred by senders and that are delivered to miners.


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This depends on your requirements, and can't be answered simply. To help guide your thinking, I'd suggest: 1) Is a blockchain really needed? You have said you are new to this space, so perhaps review your requirement against the charts here: https://medium.com/@sbmeunier/when-do-you-need-blockchain-decision-models-a5c40e7c9ba1 2) Public or Consortium ...


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This is a fee owed to the miner, rather than one they've incurred. If you look at the final entry - transaction fees credits - it starts with select from_address as address, and as the sender of the transaction, the from_address is clearly going to be the one paying the transaction fee (with the miner therefore receiving it). (In double-entry bookkeeping I'...


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There are lots of different ways you could manage writing this data to ethereum. Depending on how big your JSON files are / how many json files you'll need to publish, this is a potential solution. Deploy the contract below and transact with the writeJsonFile to emit JSONFileEvents from this smart contract, these events will be stored in the blockchain and ...


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We have curating such tools. Use and review them to help others. Smart Contract Monitoring


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Everything (no exceptions) starts with a transaction signed by an externally owned account (EOA). Signed transactions are sent to the network and included in a block. Blocks establish the canonical transaction order. (Peer discovery, gossip and mining.) Ordered transactions are processed by nodes as the blocks arrive. To deploy that contract, first, it is ...


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The code you pasted is code for creating a smart contract. So that is a program running inside the Ethereum blockchain and users of the blockchain can interact with the smart contract. Everything the contract does happens inside the blockchain. Now if I just copypaste that code (or any other code to create a smart contract) to some editor it obviously is ...


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You can think of this example. When people talk about Home Automation, it deals with personal data like the door lock, lights on/off, heart beat from smart watch etc. When you talk about a Blockchain, the need for various nodes that provide some transnational data is the common expectation. So in order to combine these two technologies, you might want to ...


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The yellowpaper (version 7e819ec - 2019-10-20) section 6.1 Substate includes a description of: indexable ‘checkpoints’ in VM code execution that allow for contract-calls to be easily tracked byonlookers external to the Ethereum world (such as decentralised application front-ends). The yellowpaper preceded the event terminology, but an event is a way ...


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In https://blog.ethereum.org/2015/11/15/merkling-in-ethereum Vitalik Buterin gave an example of using the different trees (transactions, receipt, state trees). Has this transaction been included in a particular block? Tell me all instances of an event of type X (eg. a crowdfunding contract reaching its goal) emitted by this address in the past 30 days What ...


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Receipts are basically for proving logs and events, rather than details of a transaction. In https://blog.ethereum.org/2015/11/15/merkling-in-ethereum Vitalik Buterin gave an example of using receipts, as well as other examples that can be answered with Merkle proofs: Has this transaction been included in a particular block? Tell me all instances of an ...


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Your understanding is intuitive but the actual situation calls for inverting the conceptualization of tokens. First, ETH is a special case since it's the native currency OF the network. Tokens are contracts that run ON the network. They have commonality because they, generally, adhere to the ERC20 standard. Your contract will know when it has received ...


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In general, every coin has its own contract which does the book-keeping (which address owns which amount). If the address of the contract for a coin is known and the coin contracts implements one of the well-defined interfaces like ERC20, then the explorer has enough information to sort out which coin was sent to which address.


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