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6
votes
2answers
1k views

Can I pass arguments to a .js script on Geth?

I'm starting to get a handle of Geth, especially the scripts, following this and this. I have scripts that create contracts and call functions, but I don't know how to pass arguments to a script. ...
1
vote
0answers
453 views

Parity --warp stops syncing at block 2,626,057 [closed]

The title says it all. I'm testing parity with --warp pruning fast. Was thrilled having started a node in ~10 min and synced the chain in ~1,5 hours. One day later I try to do transactions with the ...
2
votes
2answers
451 views

Where can I see the output of Solidity's sha3 function?

I have written the below code and it runs perfectly. After mining and passing the values along with certain gas value, i get transaction hash as output on the geth console. Now i want to know the ...
11
votes
1answer
5k views

Ethash vs Equihash in terms of memory hardness?

Ethereum's Ethash was designed to be memory hard with the intention of making the mining process ASIC-resistant. Zcash's Equihash algorithm also promises the same. How do these two PoW systems compare ...
2
votes
0answers
908 views

Creating keyfile and address from private key [duplicate]

What is the logic behind Ethereum creating key file and account account address from the private key. I am able to import a ECDSA private key to create an account. Same account address is generated ...
2
votes
1answer
734 views

Ipfs. Adding files using http request in meteor

Good day, I've spent some time trying to upload file to ipfs using http request (from meteor). Meteor.startup(() => { // code to run on server at startup Meteor.methods({ ...
2
votes
1answer
5k views

How to use keccak256 in Solidity?

I have created a Student registration form and taking input as firstName, lastName and studentRegId. Something like this: contract Unique { string fn; string ln; bytes20 val; bytes32 sId; ...
2
votes
0answers
331 views

Using Truffle with Ethercamp Ethereum Studio

I'm trying to use the Truffle development environment inside of EtherCamp Ethereum Studio. My main reference is this issue in the Truffle issue tracker. It suggests using eth-lightwallet and hooked-...
2
votes
1answer
1k views

invalid address <br> at anonymous:1:1

I wrote the following contract and instead of returning a hash value it is giving me the following error: invalid address <br> at web3.js:3887:15 <br> at web3.js:3713:20 <br> ...
15
votes
9answers
19k views

How to get testnet ether?

https://youtu.be/NBwRXpCQta8 I watched this video and followed it. But my account test ether is zero. I used faucet.ma.cx:3000 site too. But test ether is zero.
4
votes
1answer
951 views

How to deploy dependent contracts with Ethereum Wallet

I have two contracts (i.e. contractA, contractB) located in different files (i.e, contractA.sol, contractB.sol) to deploy. The contractB is dependent on contractA. In contractB.sol, import "...
4
votes
1answer
394 views

Can Two Contracts Import Each Other?

I have two contracts with variables and functions that each should need to reference/call. I would prefer to separate the contracts, as different user groups would be accessing each. Can two contracts ...
2
votes
1answer
735 views

How do I find a list of the Golem Network Token (GNT) TokenTrader contracts?

The Golem Network Token (GNT) TokenTrader contracts enables the trustless and decentralised sale of GNTs for ethers (ETH). A seller deploys one of these TokenTrader contracts using the ...
1
vote
3answers
566 views

Geth sync and exit

I don't usually keep my Geth instance running, but I would like to keep my Ethereum blockchain synced so that starting Geth is not slow. I reason that I can create a cronjob for this. So my question ...
4
votes
1answer
1k views

How deploy a smart contract with meteor and metamask?

I will deploy a smart contract with meteor and matamask. My code in main.js : var inactivityTime = 1000; var continuityContract = web3.eth.contract(Continuity.abi); var continuity = ...
3
votes
1answer
2k views

string and Error: new BigNumber() not a number

I am trying to generate a hash of a file and send it to a contract. But I am getting an error Error: new BigNumber() not a number: a8fac6cf98e6f5e9a76ae1f8064e505b(…) Here's my contract code: ...
1
vote
1answer
758 views

How to interact with Smart Contract in private network with 3 nodes using Mist?

I'm looking for a method to interact with a smart contract deployed from the official Ethereum wallet. My client is Geth,and I've synchronized 3 nodes. How is possible to recall a simple method of ...
23
votes
1answer
8k views

What is Parity's “warp” sync, and why is it faster than Geth “fast”?

A follow-up of one of the classic questions on this site: One of the answers to this question suggested using Geth's --fast flag to help quickly synchronise the block data. Now, parity comes with ...
7
votes
1answer
532 views

How to install and test Viper programming language?

Viper is a new functional, strongly typed, bounds/overflow-checking, fixed-point-decimal python syntax-based HLL. The repository does not inlcude any documentation yet. I built and installed ...
1
vote
1answer
439 views

Contract public variables stay undefined. Why?

I have a contract that looks like this: contract MainContract is usingOraclize { ... address minter; uint public returnRate; ... function MainContract(uint _returnRate) { ...
2
votes
1answer
139 views

Is it possible to link contracts to existing libraries from within geth console?

I've been making and deploying contracts and libraries, deploying libraries first and then using the binary output from e.g. $ solc --bin-runtime test.sol --libraries TestLib:...
2
votes
0answers
110 views

GasLimit check failed for header -1 when mining in private chain

On a machine with geth and geth --testnet running I would like to creat a private chain as well. I have created a private chain with the following genesis.json { "name": "hackathon", "engine"...
2
votes
1answer
55 views

Unable code fails when initializing mapping of structure

Hi I have this structure, but when I call the function joinLottery, the mapping for gamblers[0] is not updated. Need help to understand why is this happening. struct Gambler { uint token; ...
4
votes
2answers
1k views

ERC-20 tokens and freezing accounts

For the compliance reasons I need to implement account freeze functionality in ab ERC-20 token. Initially, issued tokens are not transferable until the address holder goes through Know Your Customer ...
3
votes
1answer
352 views

Please Help! ReplaySafeSplit contract not working after sending too much ETH

I am hoping someone has a answer to what I think is a relatively simple question. I started splitting my ETC from ETH using the ReplaySafeSplit contract. Some test and smaller transactions worked fine,...
3
votes
0answers
185 views

Ethereum wallet shows “no accounts yet” and 0.00 balance [duplicate]

I last used Ethereum wallet in June or July this year. Yesterday I upgraded on macOS to 0.8.7. It is syncing very slowly; at this rate it will take a week to finish the remaining 189,000 blocks. In ...
3
votes
1answer
138 views

If two keystore files have the same password, can it be figured out?

If two different keystore files have the same password, can it be figured out? Suppose I publish to the internet two keystore files corresponding to two different addresses. The files have the same ...
15
votes
2answers
3k views

How can ERC20 token implementations be verified?

The ERC20 Token Standard is great, in that it allows wallets, exchanges, and client implementations to allow users to interface with a variety of tokens in a common way. But how can one of these ...
15
votes
3answers
7k views

How to generate a unique identifier in Solidity?

I am making a student registration form and need a unique identifier for them. Are there any methods in Solidity that will give a unique number for every student that registers?
4
votes
1answer
213 views

DEVgrants program still alive?

is the DEVgrants program to promote the development of ethereum dapps still alive ? https://blog.ethereum.org/2015/04/07/devgrants-help/
4
votes
0answers
309 views

How to deploy a contract with inputs by using JSON-RPC? [duplicate]

I can deploy a simple contract without any input by using JSON-RPC, like: curl -X POST --data '{"jsonrpc":"2.0","method":"eth_sendTransaction","params":[{"from":"sender's address","code":"compiled ...
5
votes
1answer
400 views

Where can I find the DHT in my system?

Information about peers is stored in a Kademlia-like Distributed Hash Table in my node. Where is it stored? I know that admin.peers command gives me a list of nodes but I want to see the actual ...
2
votes
1answer
4k views

How to retrieve current date and time in solidity? [duplicate]

I need to store date in one variable and time in variable. Are there any methods to get date and time in solidity?
3
votes
3answers
2k views

ConsenSys/eth-lightwallet - How does it work?

I am using example webwallet.html from https://github.com/ConsenSys/eth-lightwallet It seems to work for me but I am confused on how does it actually work. Can someone explain to me please? Here is ...
3
votes
1answer
159 views

Parity in --geth mode brings “unknown api” error

I'm trying to migrate wallets from Mist to Parity. Parity is already fully synced and after using --import-keys I was able to import old Mist accounts into Parity. But the wallet contracts are missing ...
4
votes
1answer
2k views

Parity client from command line

Follow up on this post Does parity include a console? It is possible to have a JS script -with web3 nodejs library- running in a linux machine which only has installed parity as a client (no geth)? ...
5
votes
1answer
445 views

How many bootnodes are hardcoded into Ethereum clients?

Bootnodes are supposed to act as entry points for new nodes into the Ethereum network. How many such bootnodes are hard-coded into Ethereum clients? Also, Who maintains these bootnodes and what ...
3
votes
2answers
259 views

host:port for testnet and mainnet

I am testing my Dapp and need host:port for testnet and mainnet. Please can you let me know where can I find these urls? Also, what if the url (host:port) i provide and it goes down?
4
votes
1answer
259 views

Syncing filled all my space, where is the data and how do I remove everything as clean as possible?

I'm running geth on a distant linux Ubuntu machine, I have a total of 12Gb disk space, I thought that would be enough, but it wasn't. I only had the minimal LAMP settings, I installed Geth with these ...
14
votes
4answers
19k views

unable to connect Ethereum node even RPC port: 8545 is open

I have created my private Ethereum blockchain network. From different servers I am able to connected and added into the network as peer without any problem. The way I run my server: geth --...
1
vote
1answer
313 views

Eris : error compiling contracts

i try to deploy a contact using Eris Platform, i followed the tutorial in the documentation of Eris ( https://monax.io/docs/tutorials/getting-started/index.html?redirect_from_eris=true#fnref:1 ) but ...
-2
votes
2answers
1k views

Connect Ethereum to a database [closed]

I need to create a Dapp which stores information about companies in a private blockchain. There are different institutions that collect company information and then the information should be retrieved ...
5
votes
1answer
642 views

How do you balance inline assembly blocks?

Since Solidity 0.4.3, the compiler now shows warnings when a block is not balanced. For example: Error: Inline assembly block is not balanced. It leaves 1 item(s) on the stack. I've tried finding ...
9
votes
2answers
1k views

Running Mist with INFURA

Is it possible to run the Mist browser with an external ETH client like INFURA? Yes, I understand this may not be the decentralized paradise we want to get to, but I'd just be happy to run a browser ...
2
votes
1answer
252 views

Is there a distinguishing characteristic of a 'contract creation' transaction?

Look at this transaction: https://etherscan.io/tx/0x37c469573ca24f538d91f39e9d0b8d49927a36d70496ef74521cbf5c44a056d4 In geth's console, if I enter: eth.getTransaction('0x37c4...') It returns ...
3
votes
0answers
318 views

geth shows last block 0, but on import says all blocks present

I'm trying to restore a corrupt geth DB to a previous version, when I run geth it says I1109 17:36:34.009514 core/blockchain.go:213] Last header: #0 [d4e56740…] TD=17179869184 I1109 17:36:34.009547 ...
7
votes
2answers
585 views

Why is Geth trying to connect to private network IP addresses (RFC1918)

I have geth running on a Hetzner machine and I got an abuse warning from the provider flagging that my machine is sending UDP/TCP packets to private network IP addresses like for instance 192.168.., ...
6
votes
2answers
1k views

What algorithm is used to encrypt a private key?

In my understanding, private keys are encrypted with some symmetric algorithm, so you can't access them without passphrase. What is it called?
5
votes
1answer
868 views

Is it possible to regenerate the private key file?

I have created an account in testnet which I know the address and the password of, but I did not backup the private key file. Can I somehow create the key file again using the password? Or is my ...
3
votes
1answer
1k views

Printing into console: Events TypeError - 'watch' is not a function

Printing into console I need to print out values like these green lines: 1) Tried returning When I call a function that returns a string, the hexa transaction address gets printed instead of the ...

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