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Questions tagged [smartcontracts]

Smart Contracts are small computer programs stored inside the Blockchain that can update themselves, store their own state, and own digital assets.

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Is it possible to create an application on a block chain without a native coin

Hello guys I've been pondering on some idea of creating a forex broker which will work on a block chain but i have some worries which I'm confused about... How can transactions go on in my broker if ...
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Is it posible to create a transaction output that can either be reddemed by privK of Addr A or by privK of Addr B AFTER certain blockheight?

I am thinking about how to secure your Bitcoin savings. One idea I had was to create sort of a "backup" address B for an address A which stores the bitcoins. So what I want to achieve is that you ...
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Are there any smart contract systems that are self executing without the need to have an external process to initiate a smart contract?

Doing some research on smart contract systems. I want to create a self executing smart contract that can monitor external data like say the weather from an api. Currently ethereum and other smart ...
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Is “Hawk” (a decentralized smart contract system) able to provide acceptable privacy for blockchain?

According to the Hawk paper: "Hawk, a decentralized smart contract system that does not store financial transactions in the clear on the blockchain, thus retaining transactional privacy from ...
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Ardor Lightweight Contracts: (Almost) trustless way with new Phased Transaction type?

I asked that question on Bitcointalk, but got no response so far. As Lior has proposed to make Stackexchange the main medium of exchange about Ardor I'm asking here. As I read in the FAQ, the main ...
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35 views

Could Taproot or Graftroot enable the execution of complex scripts?

From my understanding, Taproot uses a Merkle Tree structure whose root represents the outcome of a script. That representation is in the form of a signature that may unlock the inputs associated with ...
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179 views

Template of a DAO?

Where can I find a simple smart contract template of a DAO? not The DAO, but a Decentralized Autonomous Organization, rules, codes, bylaws, responsibilities, etc.
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49 views

How is a node selected to run Smart Contract in Ethereum

A node that runs a smart contract will be paid with GAS. How is this node selected? I guess this node should be trustworthy. Or multiple nodes are running the same smart contract just to make sure ...
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Hash Time Locked Contract (HTLC) using bitcoin-qt [duplicate]

Is it possible to manually create a Hash Time Locked Contract using the bitcoin-qt command line? I have dabbled with manually creating createrawtransaction / sendrawtransaction using the bitcoin-qt ...
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33 views

Token vs contract - are they the same?

The Ethereum ERC20 token is also the contract. The token can never live without the contract. The name of the contract is the name of the token. In the code, the keyword is contract and not token. I ...
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59 views

Examples and Tutorial on how to use lightweight smart contracts on Ardor?

I've just read about Ardor's lightweight smart contracts: https://medium.com/coinmonks/lightweight-contracts-b738b6e29377 Is there an example and tutorial of how to make use of these smart contracts ...
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Funds through ICO

Is it possible for a company to raise funds through an ICO even if it is not a startup? For example: Say company X manufactures chocolates but now it wants to further expand its operations and needs ...
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Purpose of token standard interfaces when implement smart contract

I am studying to write smart contract and see that there are some token standards such as ERC20. My question is: what is the purpose of those standards ? Why do we need to add those interface to our ...
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Aborting a three-way swap

Suppose Alice has 1 BTC, Bob has 1 LTC, and Carol has 1 NMC. Alice wants NMC for BTC, Bob wants BTC for LTC, and Carol wants LTC for NMC. Assume each cryptocurrency has the same value and can be 1-to-...
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Is it possible to create a Dapp on top of Bitcoin?

Is it possible to create a dapp on top of bitcoin similar to how it can be done with ethereum? Can it be just as capable as ethereum?
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36 views

Reveal a result after block height

So imagine we have 5 different parties, all of these parties test if a particular thing is true or false over the course of 24 hours. The network needs to come to a consensus about the majority ...
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2answers
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Does blockchain have any value if you trust all nodes?

If we are designing a new project or application whatever it is, and you can trust all nodes, should we still consider blockchains in the architecture? I saw this video of IBM and I was wondering ...
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Smart Contracts on Bitcoin's blockchain

Will projects build on top of Ethereum's blockchain be able to transit to Bitcoin's blockchain when the smart contract platform is up and running?
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166 views

Questions about blockchains, network trust and why becoming a node? [closed]

everyone, I'm a software developer and I'm striving to understand the concepts behind blockchain and the projects running on them. I'm not sure if this is the correct place to ask these questions, ...
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While creating new crypto using fork need to generate smart contract? [closed]

I have 2 questions for creating nee crypto currency using fork. 1.) I have created one new crypto coin which is called mindcoin, now should i generate smart contract for deployment my currency in ...
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Crowdsale and Smart Contracts (Number)

I just need a quick clarification for crowdsale. If i have 3 rounds of crowdsale, do i need to write and execute 3 different programs at different times or submit all at a time under one program? ...
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Smart Contract Execution

If I have a Blockchain which consists of few smart contracts. Let's say that the Blockchain consists of 2000 blocks. When a new block is added to the Blockchain then does the smart contract runs on ...
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119 views

ETH smart contracts v/ traditional

total newb here. I purchased some ETH on an exchange which uses smart contracts, it is in that exchange wallet. I have another wallet which does not support smart contracts, only "traditional" ETH ...
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How does the Smart Contracts work in a blockchain

I am relatively new to blockchain technology, and my only knowledge is relative to the way bitcoin blockchain works. I know it is based on mining and and transfer of value that gets scarce whenever ...
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How do you see if your wallet supports ERC-20?

I have a wallet on an exchange and would like to know if there is a rule of thumb to identify if your wallet supports ERC-20. Any help would be appreciated.
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238 views

How to send Ethereum from a “paper wallet address” to another address using an API?

I have an "Ethereum Paper Wallet Address" and this address has $5 USD amount of Ethereum. I want to transfer that ether to another Ethereum address using an API. Please let me know if any more ...
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Conditional based Crypto based on Smart Contracts

Is it possible to store an encrypted message in the blockchain that reveals itself only when a particular condition is met? I think that the conditional disclosure can be done with Smart Contracts, ...
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200 views

Are Ethereum Tokens issued in an ICO similar to stocks on a stock market? [closed]

Are Ethereum Tokens issued in an ICO similar to stocks on a stock market? In which ways are they similar, and in which ways are they not? To give some background to my question. I just joined an ICO ...
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Where/how is smart contract's state stored?

There're some smart contracts that only checks whether certain conditions are met. On the other hand, there're some other contracts that keep some state and the state changes by transactions calling ...
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2answers
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How to store private data in blockchain and smart contract

Following my previous question on this topic Is there a way to store and share a private key through blockchain?, I might have a solution but I would like to improve the process. Image that A is the ...
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Why can't smart contract code just be stored on an immutable blockchain an just have another system execute this code?

I understand that a smart contract is just a fancy term for code that just does something with accounts in an immutable blockchain. A good example is, if you wanted to send your friend 1 coin a week ...
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461 views

Bitcoin and Smart Contracts

I have recently come across the features of ethereum and the idea of smart contracts. I like the concept of smart contracts however as a currency, I much prefer the bitcoin to the ether. Is there ...
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1answer
291 views

What is the status of smart contracts in bitcoin?

Are contracts described here already available for use? This source claims that "Ethereum style contracts" will be available in June. Is this correct? How are Ethereum style contracts different from ...
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bitcoin smartcontract feature

I am a noob, so please bear with me. I'm wondering whether the Bitcoin Core team plans to integrate a smart contract feature evolving the Bitcoin scripting language in a more sophisticated one in the ...
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How do I program smart contracts?

Is there a guide to learn how to program smart contracts for the Bitcoin blockchain?
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Does bitcoin have the potential to be subject to a hard fork where miners are forced to choose which fork they will accept, like Etherum?

Some background (Taken from Quartz): Ethereum is similar to bitcoin, but it also supports smart contracts, agreements written in computer code that execute automatically when conditions are met....
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340 views

Smart contracts in bitcoin

Is it possible in bitcoin to start a smart contract preloaded with some amount of money. And if some other user is ready to pay to the smart contract a certain amount of money, the smart contract ...
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93 views

Issue transaction without being online

Is there some way in which User A who could load a transaction onto the block chain and if some other User B who is willing to pay User A, without User A being online could release the loaded ...
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127 views

Size of Blockchain for huge smart contracts database

Let's say I want to use smart contracts for huge collection of data. Since it will be distributed so downloading on every participant computers isn't this a huge problem ?
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Storing scripts (smart contracts) outside the blockchain

I'm following "Mastering Bitcoin" from Andreas Antonopoulos in order to understande the Bitcoin implementation. In the chapter about transactions, he points some advantages of P2SH transactions: ...
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Is it cheaper to store data across multiple instances of the same contract?

From what I understand, code is deduplicated on the Ethereum blockchain by storing pointers in new blocks to blocks containing code that is being reused in the new block. If that's the case: Is it ...
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286 views

How smart property works on basic bitcoin blockchain?

How smart property works on basic bitcoin blockchain? I am not sure that how to make token, that is tied with a particular object, on the bitcoin blockchain. I've already know I can use such kind of ...
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Bitcoin bet on price of Brent crude

Is there a place where I can bet on the price of Brent crude oil? For example, I bet 1 BTC and: if the oil price increases by 1%, I will lose the bet. if the oil price decreases by 1%, I will double ...
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Restricting transferability of Smart Contracts

Can a smart contract be created which can be exchanged once at point of sale, and only transferred subsequently through a single approved exchange? Can that be written into the contract itself?
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How to delete an element of an array in an Ethereum contract?

I am wondering - is it possible to delete a single element of an array in Ethereum without having to create a new array and copying the entire array? Reading some of the documentation, I can't seem to ...
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10k views

Is there a way to access Ethereum Smart Contract's variables by name in JavaScript?

Say I have a simple smart contract: contract Simple { string32 message; function Simple() { message = "Hello world!"; } } How can I easily access the message variable by name in ...
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1answer
669 views

In Ethereum smart contracts is it cheaper to keep all the data, or delete old data?

As I understand, Ethereum smart contracts can store data internally. I am wondering - is it cheaper for a smart contract to keep all of its data forever if it is keeping the data for any length of ...
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2answers
548 views

Who pays the fees for transactions initiated by a smart contract in Ethereum?

I am wondering who pays the fees for transactions initiated by a smart contract in Ethereum? For example, if I have a contract that simply forwards any payment made into it to someone else, does the ...
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586 views

Can an Ethereum contract be updated without having to be re-submitted?

I am wondering - can an Ethereum contract be updated without having to be re-submitted? Say, if I find a bug in my contract, can I fix it without having to create a new contract and making my ...
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Is it possible to schedule function calls to an Ethereum smart contract?

I am wondering - is it possible to schedule or somehow trigger function calls to an Ethereum smart contract based on the current block height or timestamp? This would involve some pre-payment of gas ...