Raghav Sood
  • Member for 3 years, 10 months
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Why are Ethereum addresses hashes of public keys?
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10 votes

Indeed, ethereum's address reuse renders the "protection against an ecc public key attack" argument null. For externally owned accounts, using the public key directly would likely not result in any ...

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Block time and confirmation time
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9 votes

Block time is the expected interval between two blocks. For ethereum, this is around 15 seconds. For Bitcoin, it is 10 minutes. The number of confirmations is simply the number of blocks that have ...

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Why people use public function that just calls an internal function?
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7 votes

Open Zeppelin's contracts are often structured to be editable/extendable, as opposed to what might be considered a "normal coding style". Perhaps you want to perform some additional checks before ...

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Solidity accessing old logs
5 votes

Logs in Ethereum are a special construct, and have a specific meaning. You don't appear to be using any in your contract. What you do seem to want is retrieving the state of the contract at some ...

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Is it possible to retrieve/query data stored in the blockchain
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5 votes

It is not possible to query data stored in the blockchain. One can store data and it will be there in the blocks of the blockchain but one cannot retrieve data stored in the blockchain. This is ...

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How to read data from smart contract using web3.js?
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5 votes

Etherscan is only able to provide that for contracts that verify their source code, or for contracts that follow a specification, such as ERC20. This is because reading a contract (or writing it) ...

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Is it possible to have multiple private keys for a single public address?
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4 votes

An address is simply the last 20 bytes of the keccak256 hash of the public key. For ecdsa algorithms (and RSA), each private key has exactly one public key. However, when this public key is hashed ...

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how to easily transfer ERC20 token from 1000+ accounts which has no ETH in it initially?
4 votes

If you are using 1000 externally owned accounts, this is not possible. The only way you can have a separate address pay for token transfer costs is by having each user wallet be a contract, and the ...

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Type address is not implicitly convertible to expected type contract ERC20
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4 votes

Change token = 0x0f26c1c05f1bbBC7Eff0488F1a98619e8a9758cf; To token = ERC20(0x0f26c1c05f1bbBC7Eff0488F1a98619e8a9758cf); token is of type ERC20, and you are trying to assign it a value of type ...

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Is USDT ERC20 token or omni?
4 votes

USDT has both an Omni and an ERC20 implementation. You can use the APIs of any exchange offering USDT trading for Omni or ERC20 to trade them.

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If Metamask Gas calculations are nearly perfect why do we still get out of Gas error?
4 votes

Gas estimation is not an exact science. There are certain cases when the gas estimate can be wrong, or impossible to estimate properly. Certain such cases depend on behaviour. If a contract has ...

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Is it possible to tell that two addresses were derived from the same private key?
4 votes

Technically, a private key will only lead to two addresses - one from the hash of the uncompressed public key, and one from the compressed on. Ethereum only uses uncompressed keys, so you only get one ...

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Where does Ethereum store EOAs and public keys?
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4 votes

How is a wallets public key published in the Ethereum network? It isn't. For an EOA, the address is computed as the last 20 bytes of the keccak256 hash of the public key. The public key itself is not ...

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How to add available accounts at infura HttpProvider
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4 votes

Infura is only an API provider, they do not provide a wallet or account service. When you use metamask or something similar, your accounts are stored locally, and a provider such as infura is only ...

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For sending a transaction to Ethereum, we need to be a "full node"?
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4 votes

To send a transaction to the network, all you need is a connection to it. When using geth or parity, your the nodes may not broadcast your transactions until they are reasonably close to being fully ...

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Expected primary expression error
3 votes

Your syntax error can easily be fixed by just changing &amp,& to &&. However, this will then give you a call stack size error, since you cannot return an object as large as your ...

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ERC20 verification for arbitrary address
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3 votes

It looks like they actually follow a concept of "Universes", and each universe is an instance of the following: contract Delegator is DelegationTarget { function Delegator(IController _controller,...

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ACCESSING BLOCKCHAIN ON "ESP8266" USING THE "NODEMCU BOARD"
3 votes

You cannot run geth or parity on an ESP8266, it is simply too underpowered. Your best bet would be to expose the RPC on an actual node, and invoke the calls over http from the ESP.

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I am kind of new to ethereum, but can someone explain me difference between metamask accounts and geth account new
3 votes

geth at its core is a node software, whereas metamask is a wallet and web3 provider. Geth also offers some wallet functionality. An externally owned account on ethereum is backed by a private key. ...

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If I import Ownable and MyClass inherits from it, do I need to migrate the Ownable at all?
3 votes

You do not need to explicitly deploy any contracts you inherit from, or any contracts that are deployed during the deployment of another contract. For instance, if you have: contract A is B { } ...

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why out of gas when gasLimit is not reached
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3 votes

If you look at the parity trace for the transaction, you can see that it runs out of gas on a call from 0x4ceda7906a5ed2179785cd3a40a69ee8bc99c466 to 0x092988fc1090ff8f924b8f9cc71350e90ca446cd, which ...

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duration limit for unlockAccount()
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3 votes

According to the geth source, there is a max check for the time, which is calculated based of the MaxInt64 value, and ends up as 9223372036 seconds, or roughly 292 years. // UnlockAccount will unlock ...

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is ether itself an ERC20 token?
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2 votes

Ether is not an ERC20 token - however, the WETH contract creates Wrapped Ether, which is an ERC20 token backed 1:1 by Ether.

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Why geth switch to full node when starting
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2 votes

A fast sync will switch to a full sync mode as it reaches the chain tip, once enough of the state trie has been synced in fast mode. Going forward from that time, it will sync in full mode and ...

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Full Node Bigger Than Online Reports?
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2 votes

There are essentially four modes of operation for geth: light - in this mode, you sync next to no data locally, instead relying on other full nodes that have agreed to server light peers. It's more ...

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msg.sender problem for calling ERC20 token contract from another contract
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2 votes

If you want the tokens transferred from the user's account, the correct way is to first ask the user to call approve for your Adoption contract's address, and then use the transferFrom function within ...

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transaction fails due to out of gas in mainnet
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2 votes

Your transaction is failing with an Out of Gas error due to one of the calls within your contract not providing sufficient gas to complete its operation. If you look at a Parity trace of your ...

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Why ethereum dons't store transaction signature?
2 votes

A transaction will not be mined without a valid signature, under current consensus rules. Thus, if it has been mined, a valid signature was provided. This means that you can retrieve a historical ...

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Manually specify extra gas amount required in solidity for apps such as metamask
2 votes

I believe after much research I've pinpointed this problem to the contract making extensive use of block.timestamp and "now" for pseudo-RNG purposes (which I'm aware of the limitations). Such function ...

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OMG Tokens locked in smart contract - onlyPayloadSize
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2 votes

Your issue is likely unrelated to payload size, and related to the fact that your token interface expects transfer() to return a bool. OMG is one of a handful of major token contracts that deviates ...

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