All Questions

5
votes
1answer
741 views

Why is fast sync not working with geth 1.1?

When I run geth --fast I get: Incorrect Usage. geth [global options] command [command options] [arguments...] VERSION: 1.1.0 [...] flag provided but not defined: -fast How do I fix this?
4
votes
1answer
792 views

How can I check which network I'm working on?

When I start eth I get the following header: $ eth (++)Ethereum Beware. You're entering the Frontier! [...] I think i followed the instructions for working on a private network (because i just want ...
3
votes
1answer
118 views

Potential security issues warning banners with Ethereum

I'm testing ethereum and the foundation websites states that Frontier is an early access to the Ethereum network. Bugs and security issues might be present. Before downloading you have to agree ...
1
vote
0answers
83 views

Why is my node taking so long to sync? [duplicate]

I downloaded the ethereum wallet, and its taken a few days yet its still syncing. Im on block ~701,000 thus far. Is something wrong? Is it supposed to take this long?
7
votes
2answers
725 views

Can I compile a smart contract without removing the line breaks?

According to an official document, compiling a smart contract needs to remove all the line-breaks in the contract's source-code: If you have the SolC Solidity Compiler installed, you need now ...
7
votes
1answer
1k views

Does a mining reward transaction have a hash?

I can't find a mining reward transaction hash for a given block. I can see the block hash, all the transactions inside the block, etc. But the mining reward transaction is not listed among the details....
15
votes
5answers
16k views

Is there a C# implementation available for Ethereum?

Is there a C# / .NET / Mono implementation available for Ethereum to interact with nodes and/or the blockchain?
14
votes
4answers
4k views

How do Ethereum clients generate unique addresses?

How do Ethereum clients, like Ethereum Wallet or Eth-Lightwallet, generate unique addresses that haven't been used before, and what is the likelihood that these addresses have been used?
15
votes
2answers
4k views

Is it safe to reuse Ether addresses?

I believe it's viewed as unsafe in Bitcoin because of the way transactions are signed. Is this also true for Ether addresses?
16
votes
2answers
20k views

Can I set the gas price to whatever I want?

The default gas price is 0.02e12 Wei. But while creating transactions on the command line or Geth's Javascript console you can define your own gasPrice: web3.eth.sendTransaction({/* ... */, gasPrice: ...
3
votes
1answer
169 views

What options are suitable for Ethereum addresses with checksums?

Since Ethereum addresses don't have checksums, should ICAP addresses (which do have a checksum) be proliferated? Or are there other options more suitable for the proliferation of checksummed ...
37
votes
2answers
20k views

Is there a limit for transaction size?

Is there a theoretical limit for transaction data size when you send a transaction to Ethereum network? Ref. Is there a (theoretical) limit for amount of data that a contract can store?
7
votes
1answer
2k views

How can Hooked-Web3-Provider and Lightwallet work together?

Does anyone know some good working examples of the Eth-Lightwallet and the Hooked-Web3-Provider working together? I was trying to get https://github.com/ConsenSys/eth-lightwallet/blob/master/example/...
11
votes
4answers
2k views

Can there only be one instance of a contract?

Say we have: contract TestFooContract{ //bunch of stuff and state } Does this mean that there is only 1 "TestFooContract"? Or can I instantiate 10 of them? What if I want multiple of these contracts?...
12
votes
4answers
7k views

What Hierarchical Deterministic (HD) wallets are available for Ethereum?

A Hierarchical Deterministic (HD) wallet has some nice features such as easier backup (instead of needing to backup multiple keystore files and the passwords for each of them). Are there any ...
5
votes
1answer
163 views

How compatible are ICAP addresses with HD wallets?

A Hierarchical Deterministic (HD) wallet has some nice features such as easier backup (instead of needing to backup multiple keystore files and the passwords for each of them). Since ICAP addresses ...
3
votes
1answer
324 views

Is there a way to convert a regular address to an ICAP address?

The ethkey guide mentions how a regular address can be obtained from an ICAP address. But it doesn't mention how an ICAP address can be obtained from a regular address. Occasionally, however, it's ...
6
votes
1answer
2k views

What is an ICAP address?

It appears ethereum is using plain hexadecimal addresses like 0x0092e965928626f8880629cec353d3fd7ca5974f for now. I noticed, the ethereum C++ implementation outputs so called ICAP addresses, check ...
3
votes
2answers
2k views

Why can't I create new accounts on testnet?

So I've set up a new testnet using geth --identity "NNode" --genesis /home/test/Documents/Ethereum/genesis.json --rpc --rpcport "8080" --rpccorsdomain "*" --datadir "/home/test/Documents/Ethereum/...
10
votes
1answer
646 views

Given a contract address, can I determine when the contract was deployed?

Ideally the solution would use web3, but other solutions are acceptable. Motivation: Event lookups can be passed fromBlock field. If I know the block a contract was created, I can more accurately do ...
9
votes
2answers
5k views

How to concatenate a bytes32[] array to a string?

I am passing an array of bytes32 to my function. This array can contain numbers or hashes etc. to identify an object. In a new use case I want to pass a URL to this function by splitting the URL into ...
3
votes
3answers
2k views

What is the best language to start programming in Ethereum?

I have an introduction to C++ under my belt (very simple stuff), and other skills like an occasional R script, that's about it. Where should I go from here?
4
votes
1answer
2k views

Where exactly do DApps run? Who gets rewarded for running them? [duplicate]

So I am currently running a full node, as well as a GPU miner. I am curious first of all where do DApps get run? They wouldn't make sense to run on a GPU as they aren't very parallizable, so I am ...
6
votes
1answer
331 views

Is it possible to make Zeronet p2p websites as client of Ethereum Dapps?

Is it possible and does it make sense? You can browse some cool P2P-websites (work without any servers) inside the network through this gateway. Or you can browse them without any gateways if ...
5
votes
2answers
881 views

All my mined coins are going to address 0x000000

I have an ethereum miner up and going for about 24 hours now. For the first 15 hours or so I saw the following text repeated on the screen (each time updating only the timestamp). 23:17:27.282|...
6
votes
1answer
113 views

Can I test different OS and combine the keystore folder later?

I have to move from Linux to Linux but also want to test under Windows. Is there any issue in running accounts and wallets under the different OS with a view to combining them under a single OS at a ...
6
votes
0answers
331 views

Is there a SetTimeout function in Solidity? [duplicate]

Essentially, is there a SetTimeout in Solidity? creationTime = now; lastBlockNumberA = block.number - 1; first = lastBlockNumberA; if(now >= creationTime + 1 days){ lastBlockNumberB = block....
6
votes
1answer
1k views

Is there any lightweight JS library that generates Ethereum addresses from 256-bit private keys?

I have a 256-bit private key and I want to get its public address without having to install Geth (which is quite heavy) on the machine. Is there any small JS lib that does that?
14
votes
3answers
2k views

Accessing past values of Smart Contract variables

I would like to know if is possible to inquiry variable values using older blocks. For example I have contract Simple { string32 message public; function Simple() { message = msg....
7
votes
1answer
1k views

What reputation systems are implemented on Ethereum? [closed]

I'm looking into finding some sort of reputation system on Ethereum. Are there any projects out there already that do this? I found a DEVCON1 video about reputation systems and a few people discussing ...
3
votes
1answer
955 views

Trying to mine - AlethOne on OSX is not doing anything

I have geth on an OSX retina iMac 5K and got it working and synchronized. Tried running AlethOne and it just sits there displaying Status 11:05:57 New block#0 regardless of whether I "start mining" ...
3
votes
0answers
695 views

Checking for empty mapping element [duplicate]

What is the best way to know if an element is " empyt " inside a mapping ? For example mapping ( address => uint) balances; If the user already used the contract there will be an address => "...
10
votes
4answers
877 views

Unable to make greeter contract

For the past 7 days I've been trying to make the greeter contract, I've been through 4 different physical computers in 2 different locations and have tried multiple different ways on 3 different ...
4
votes
3answers
418 views

Why isn't msg.sender.send getting called?

Contract code: function rand( uint256 seedB ) returns (uint256){ //define seedA variable uint256 seedA = 1; uint amount = 1 finney; if (seedA == seedB) { msg.sender.send(...
33
votes
2answers
9k views

Is there a (theoretical) limit for amount of data that a contract can store?

Is there a theoretical limit to the amount of data that one contract can store while running in a private net in which gas is not a concern? Context: In a financial Dapp which is to replace global ...
24
votes
2answers
13k views

How many transactions can the network handle?

The voting on ethereum analysis by Dominik Schiener calculated that it would take 40 days to hold the UK general elections on the ethereum blockchain due to the transaction and gas limits. I redid ...
9
votes
2answers
4k views

Are there other Vanity Address generators available?

Are there any Ethereum vanity address generators available other than: Vanityreum (python) Vanieth (go) Which is the fastest? Can they be optimized further? What is the use-case of vanity ...
15
votes
1answer
2k views

What is embark?

What is the embark framework? Who can use it, who should use it? And what are the benefits?
18
votes
1answer
4k views

What is truffle?

What is the truffle framework? Who can use it, who should use it? And what are the benefits?
4
votes
1answer
313 views

Why does Ethereum POW work fine in spite of short confirmation time?

Bitcoin confirmation time is about 10 mins. Ethereum confirmation time is about 12 sec. Why does Ethereum POW work fine even though confirmation time is shorter than Bitcoin's?
5
votes
3answers
2k views

How to compare msg.data (calldata) data type to an integer data type uint256?

As per my question here: I need to compare msg.data (specifically, numbers that are sent with the sendTransaction data object) to a data type of uint256 within my contract. How is this possible?
11
votes
2answers
198 views

How dependent is the ethereum client on the router and DNS being trusted?

Another way to put it: what is the root of trust for a full client on a network that has a potentially untrusted (or "owned") router+DNS? As I was going through the ethereum wiki semi-randomly, I ...
5
votes
1answer
1k views

Exception in Contract Reverts Entire Stack, Uses all Gas

I added a check to make sure when I send ether that if it fails, I attempt to abort the transaction using a throw. Per example here: Solidity Exceptions When make a call to a function that does ...
17
votes
4answers
5k views

Is there any safe way to send money from a cold wallet, using an untrusted computer?

You have 2 computers. One is 100% offline and, thus, trusted. Other is online. Private keys are stored on the offline computer and the online computer has no access to it. Is there any way to sign a ...
13
votes
4answers
7k views

How to run Ethereum Wallet on a custom chain?

So I downloaded the Ethereum Wallet I know you can use a custom directory by running geth first with the datadir flag set up, and then launching the wallet. But besides a custom directory, I want to ...
7
votes
1answer
553 views

How could Banks or Accounting Firms use Smart Contracts?

I keep reading how banks and accounting firms are researching into blockchain tech specifically smart contracts, but I don't quite understand how a company will apply them to current work. One way I ...
9
votes
1answer
780 views

What about illegal smart contracts?

Trying to get a friend excited about smart contracts I referred him to an ethereum pyramid scheme as an easy to understand example but he only pointed out that all pyramid schemes are illegal. How ...
11
votes
2answers
9k views

What is the difference between Ethereum and Eris?

When I first searched for Turing complete blockchains towards the end of 2015 Google returned both Eris and Ethereum at the top. My initial impression was that they are quite distinct. More recently ...
2
votes
1answer
64 views

What is being mined on a testchain?

If one starts the miner on geth when running in dev mode Ether is credited to the designated address (coinbase per default) but what work is done to merit the reward? I did not post any transactions.
4
votes
1answer
281 views

How to bootstrap AlethZero on Morden testnet?

I am trying to use the testnet using AlethZero. I use this command alethzero --morden as suggested in the wiki. It does not seem to connect to any peer and hence does not sync the blocks. I also tried ...

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