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19
votes
2answers
4k views

What advantages and disadvantages does Open Blockchain / Hyperledger / Fabric have over Ethereum?

Similar to this question about Ethereum and Bitcoin: What advantages and disadvantages does Open Blockchain (OBC) have over Ethereum? What can you do with OBC that you simply cannot with Ethereum? ...
4
votes
1answer
301 views

Main use cases between Open Blockchain and Ethereum

Looking at Open Blockchain's use cases and it appears a lot of these can be done or are on Ethereum, examples: multi-sig contract activation, execution, atomicity of contract execution, reusable ...
6
votes
1answer
187 views

Why do some functions from my contract end up in the ABI while others don't?

Using the greeter example, The original contracts is written with 4 methods: mortal(), kill(), greeter(), and greet(). Why then when I look at the mined contract does it show me an ABI of: { ...
3
votes
2answers
1k views

What is chaincode (Open Blockchain) and is it compatible with the EVM?

What is chaincode and is it compatible with the EVM? Chaincode FAQ says it supports smart contracts and can these contracts be deployed and function on the Ethereum blockchain?
17
votes
1answer
12k views

Mapping with array as Key Or Value data type

Is it possible to do a mapping with an Array as key/value ? Where an array would exist for each value ? I'm actually looking to store structs in a mapping but can't seem to have it work. Struct Foo{...
22
votes
2answers
6k views

Do I need a compiled contract just to get the ABI definition?

Why do I need a compiled version of the contract just to get the ABI definition? Seems like the contract address should be enough. Im very confused because I am simply trying to run a contract ...
13
votes
3answers
2k views

Company Shares on Ethereum

Shares are designed to provide owners with: ownership profits/losses How would Ethereum based ownership make sure each owner, gets their share profits? Is this even possible with Ethereum / smart ...
5
votes
1answer
801 views

Can you input decimals number in smart contract?

I'm having an issue where send 0.1 or 1.1 is saved as 0 and 1 in my contract's storage. Does anyone knows how to properly pass decimals ?
7
votes
1answer
90 views

Will contracts on Frontier be wiped before the move to Homestead?

The Frontier Guide contains instructions on how to create a Greeter contract. Those instructions contain details about how to kill a contract, and why we'd want to do that. Part of those instructions ...
6
votes
2answers
9k views

How to install eth on debian? (symbol lookup error)

I installed from the ubuntu ppa and got this error. ➜ ~ eth eth: symbol lookup error: eth: undefined symbol: _ZN3dev3eth14EthashGPUMiner14s_numInstancesE What can I do / check? I'm on debian ...
3
votes
1answer
340 views

Ethereum Wallet 0.3.9 (Mist) “could not unlock signer account” a few times today when sending a transaction

Ethereum Wallet 0.3.9 MacOS X 10.11.3 Now it works again, but for an hour I was unable to send a transaction and getting the message "could not unlock signer account". Maybe a bug? Any thoughts?
2
votes
1answer
206 views

Option to give passphrase via web interface

I am trying to run the sample web3.js code from here https://github.com/ethereum/web3.js/blob/master/example/event_inc.html I am running the geth node on testnet. However, when I try to create the ...
9
votes
1answer
1k views

What happens if you call a non-existent function of another contract that has no fallback function in Solidity?

Let's say you call a function at another contract in Solidity: contractB.doFunction() It would then match it using the function signature to run the function in contractB. If there's not match, it ...
34
votes
2answers
23k views

Solidity, create contract from contract

Based on documentation it should be possible to create new contract from contract contractAddress = new OwnedToken(name); When I invoke this method from contract, the address I receive seems to be ...
28
votes
3answers
18k views

How can I make new account by JSON-RPC?

I'd like to make new account by JSON-RPC.I've checked the wiki of Ethereum, however I could not find out how to do that. I've found call existed accounts, but it isn't what I want. eth_accounts ...
5
votes
1answer
233 views

Can I get from a transaction to contract state changes using RPC API

If I'm talking to geth using the JSON RPC API, I've found a transaction I'm interested in and I can see that it is calling a contract (data in the 'input' part of the transaction object.) Can I then ...
13
votes
4answers
2k views

How can I get a list of of transaction data which are sent to a specific contract?

I'd like to get a list of all transactions which are sent to specific contract or method of contract. What kind of way do we have to implement it?
4
votes
1answer
261 views

Will pooled staking be implemented using multisig deposits?

Would this be a valid implementation for an ether staking pool if the goal was to eliminate the need for depositors to forfeit control of their ether to the pool owner? Depositor creates a contract ...
17
votes
1answer
1k views

What is the order and concurrency behavior of multiple calls to a contract in a single transaction?

Suppose a contract has three call APIs that have side effects. What's the behavior if I try to: Call all three APIs from one address (i.e. issue three transactions if from nodejs). Are all three ...
5
votes
2answers
594 views

How do I fix Javascript stack overflows when compiling very large file with solc?

If I compile a very large file with solc the stack overflows. This will happen most commonly in node because the default stack is only 984kbytes, which is strangely what you would expect for a 1990s ...
4
votes
1answer
120 views

What fraction of pre-sale coins have been moved?

I am trying to estimate how many of the pre-sale coins are in circulation. What fraction of pre-sale coins have been moved?
5
votes
1answer
342 views

How many pre-sale addresses are there?

How many addresses did Ethereum have when it launched? In other words, how many pre-sale addresses are there?
5
votes
1answer
282 views

Is either the whisper.sh messaging app or the “Open Whisper Systems” project related to the Ethereum whisper project?

There is the Whisper "anonymous messaging app", described in this Wikipedia article. And then there is also something called "Open Whisper Systems", described in this other Wikipedia article. Is ...
4
votes
2answers
422 views

How to enable Ethereum support in the JAXX mobile wallet?

Jaxx by Kryptokit offers Bitcoin and Ethereum for mobile and browsers. I installed the wallet on my Android device. But it only offers Bitcoin functionality. I see screenshots online which displays ...
15
votes
2answers
3k views

Can a contract access another contract's storage?

I have a contract with numerous complex structs. Is it possible for a second contract to iterate over this data directly? I can't really use public accessor/getter methods as it's not possible to use ...
4
votes
0answers
697 views

Why are underscores used in front of parameters, instead of contract member variables? [duplicate]

In Solidity, for example, why: function Greeter(string _greeting) public { greeting = _greeting; } instead of: function Greeter(string greeting) public { _greeting = greeting; } The latter ...
37
votes
6answers
18k views

How do I parse the transaction receipt log with web3.js?

The event parser in web3 provides a nice parsing functionality for events, and I use it for logging all events to a file, but it's very difficult to use for looking at individual events for a ...
64
votes
8answers
50k views

How can I check if an Ethereum address is valid?

I've read many times that you should never input an address by hand unless you want to accidentally send Ether into no-mans-land. I'd like to know what those checksums might be. Is there a way to tell ...
3
votes
2answers
7k views

Can I recover an account with just the Private key (no json file) [duplicate]

I have read a few things lately That in order to securely store an account, one should save the json file and private key. I'm wondering If the json file is really needed though. Say I were to lose ...
5
votes
1answer
787 views

How can I generate a cold wallet completely offline WITH a random number seeded by me?

Requirements: 1) An account created on a raspberry pi that has never been connected to the internet ever. 2) A great private key on this account, that does not rely on any random number generator. 3) ...
3
votes
2answers
430 views

Can I use my own coin in 3rd party contracts?

I know you can create your own coins in ethereum but can they be used in 3rd party contracts that normally use ether?
4
votes
2answers
4k views

I've been mining with geth but my balance is still 0. Why?

Today I started mining ether on the main network and I see new blocks being processed in the console but my balance is still zero ether. Why? This is the geth console output: I0214 20:15:47.234020 ...
5
votes
1answer
176 views

How can I see the payouts of this Ponzi scheme dapp?

Towards the very beginning of the Ethereum release, a friend participated in a Ponzi scheme dapp by sending 1 ETH here. He was among the first! For some reason, it seems he has not received any ...
16
votes
3answers
6k views

What is the purpose of underscores in front of parameters?

I see contracts that use underscores in front of parameter names, like so: function Greeter(string _greeting) public { greeting = _greeting; } What's the purpose of these underscores? Do they ...
4
votes
2answers
187 views

What happens if demand for bonded validators is greater than 256?

This answer suggests there will be a maximum of 256 bonded validators for Casper. What if 257 nodes want to become bonded validators? Is there a race? What's the consensus mechanism to pick 256 ...
5
votes
1answer
2k views

Increment a global variable - can EVM nodes overwrite each other?

I have the following contract: contract Contract{ address minter; uint gid; //... //constructor function Contract(){ minter=msg.sender; gid=0; } function kill(){ if (msg....
13
votes
2answers
1k views

In Casper PoS, what is a finalised block?

Vitalik talks about block finalisation here, and Vlad also talks about it here. What is a finalised block? How long does it take to finalise a block? What are the security guarantees of a finalised ...
10
votes
4answers
3k views

What are the scalability benefits of PoS vs PoW?

This accepted answer claims that one advantage of PoS vs PoW is that some scalability problems can be addressed more easily with PoS What are those scalability problems? What are the scalability ...
2
votes
1answer
237 views

How will the transition from PoW to Casper's PoS work? [duplicate]

How will the transition from PoW to Casper's PoS work? Is there a spec written? Have there been any tests? Has code or documentation been written?
10
votes
2answers
1k views

What is the target block time for Casper?

With PoW, the block time is around 17 seconds. What is the target block time for Casper's PoS?
6
votes
2answers
992 views

Is there an easy, human centric way of viewing local Ethereum blockchain data?

Etherchain and Etherscan provide information about the Ethereum blockchain. What tools exist that will allow me to extract similar data from my local Ethereum (.ldb) files?
2
votes
1answer
54 views

What signatures will be used for Casper bets?

In this blog post, Vlad Zamfir describes a bet as a object with a signature. What kind of signature will Casper bets have? What is the length (in bytes) of those signatures?
4
votes
1answer
402 views

Why doesn't Ethereum do double hashing like Bitcoin?

Why doesn't Ethereum do double hashing like Bitcoin? What are the facts or theories on the security of single Keccak-256 hashing like Ethereum, as compared to Bitcoin's double hashing with SHA2-256? ...
1
vote
1answer
187 views

Does a DAO protect real inventors from Patent trolls? [closed]

The DAO is a Decentralized Autonomous Organization” (DAO); it can be defined as:- a fully automated business entity (FAB), or distributed autonomous corporation/company (DAC) is a decentralized ...
7
votes
2answers
562 views

Is it possible to invalidate a smart contract?

How can I invalidate a smart contract that has already been deployed? I might want to do so because of business reasons, and maybe beneficial network effects. Is it possible to invalidate a smart ...
2
votes
2answers
246 views

What is the network overhead of Casper?

In Bitcoin the PoW mining has very little overhead in terms of bandwidth. The miners simply need to produce the PoW, which I believe is 32 bytes per 10 minutes. In Casper I understand every validator ...
3
votes
1answer
703 views

How can I use msg.value twice?

I try to deploy the following code: contract Sample { struct Participant { address etherAddress; uint amount; } Participant[] public participants; uint public amountRaised; function() { ...
3
votes
2answers
295 views

From the solidity SubCurrency example: return statements

Obviously this is rookie question, however I do not believe Solidity docs, nor W3Schools explicitly state this. In the return statement, is the second line in the block equivalent to a second Then ...
4
votes
1answer
19k views

How long does it take for the ethereum blockchain to synchronize? [duplicate]

For the past few days I've been synchronizing my mist wallet with the blockchain (using geth). My laptop has been working all day and all night. I've already synced more than 880000 blocks. How many ...
6
votes
3answers
932 views

What is the difference between “eth.accounts” and “web3.eth.accounts”?

The instructions for creating a new account on the Geth console state: Tip: If you are using Geth then you can just use eth instead of web3.eth command. Meaning accounts can be referenced by ...

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