4 ms·

What would be an example of a "smart contract"?

by Siecje 9y ago

mianosm 9y ago
Basic smart contract found here: https://blockgeeks.com/guides/smart-contracts/ https://blockgeeks.com/guides/smart-contracts/
AlwaysBCoding 9y ago
A kickstarter clone, that could be implemented in a few lines of code on top of Ethereum.. If there is > 1,000 Ether in this contract address before timestamp x then send the Ether to the project lead, else refund all the users.
- thomk 9y ago
  Nice! Thank you. You know there are many different types of contracts, why didn't they just call it 'smart transactions'?
  - Brianne88 9y ago
    buddy recently bought a fantastic yellow Toyota Camry just by part-time work from a home pc _________http://bit.do/dnRs5 http://bit.do/dnRs5
  - fragsworth 9y ago
    Because it's conceptually more like a contract. Someone writes the contract code, and then by uploading and depositing money into the contract it's as if they signed it. After that point it works without anyone needing to trust the signer. And they can include conditions about arbitrary information that is reported on the blockchain (weather data, stock prices, etc...) And multiple people can sign these things. They really are like contracts.
JasoonS 9y ago
Their main use case is maintaining critical/sensitive state information that you want to protect via rules of interaction between multiple parties (that don't trust each other) without the need for a trusted intermediary. The contract is tamper proof and only via correctly and cryptographically signing messages/transactions intended for the smart contract will the state of the smart contract change, but only according to the rules defined in the smart contract. The (non-fintec) example I often hear about often is a voting system. (See: https://github.com/stonecoldpat/anonymousvoting https://github.com/stonecoldpat/anonymousvoting , here zk-snarks algorithm is introduced to ensure privacy) Essentially anything that requires co-ordination between parties that don't trust each other over a piece of data (a balance of money, the tally of a ballot) is a perfect use case for smart contracts. But since there is cost to running it on these secure networks it is important that they remain O(1) or at most O(n) time complexity, which for these kinds of applications is often totally enough. (eg. if (the message is signed by the 'owner') { send the funds } else { throw })
JasoonS 9y ago
Another interesting use case is for supply chain management, since the history of a interactions relating product can be documented in a secure manner Eg. you can buy a nike shoe that you can cryptographically validate that it was signed off by Nike, who made it, when they made it, when it was shipped, and even how much each of these parties got paid for their service. (Take a listen here: https://media.consensys.net/state-change-44-shining-a-light-on-slavery-eeae67594af3 https://media.consensys.net/state-change-44-shining-a-light-...)

What would be an example of a "smart contract"?

by Siecje 9y ago

What would be an example of a "smart contract"?

Basic smart contract found here: https://blockgeeks.com/guides/smart-contracts/ https://blockgeeks.com/guides/smart-contracts/

AlwaysBCoding 9y ago

A kickstarter clone, that could be implemented in a few lines of code on top of Ethereum.. If there is > 1,000 Ether in this contract address before timestamp x then send the Ether to the project lead, else refund all the users.

thomk 9y ago
Nice! Thank you. You know there are many different types of contracts, why didn't they just call it 'smart transactions'?
- Brianne88 9y ago
  buddy recently bought a fantastic yellow Toyota Camry just by part-time work from a home pc _________http://bit.do/dnRs5 http://bit.do/dnRs5
- fragsworth 9y ago
  Because it's conceptually more like a contract. Someone writes the contract code, and then by uploading and depositing money into the contract it's as if they signed it. After that point it works without anyone needing to trust the signer. And they can include conditions about arbitrary information that is reported on the blockchain (weather data, stock prices, etc...) And multiple people can sign these things. They really are like contracts.

JasoonS 9y ago

Their main use case is maintaining critical/sensitive state information that you want to protect via rules of interaction between multiple parties (that don't trust each other) without the need for a trusted intermediary. The contract is tamper proof and only via correctly and cryptographically signing messages/transactions intended for the smart contract will the state of the smart contract change, but only according to the rules defined in the smart contract. The (non-fintec) example I often hear about often is a voting system. (See: https://github.com/stonecoldpat/anonymousvoting https://github.com/stonecoldpat/anonymousvoting , here zk-snarks algorithm is introduced to ensure privacy) Essentially anything that requires co-ordination between parties that don't trust each other over a piece of data (a balance of money, the tally of a ballot) is a perfect use case for smart contracts. But since there is cost to running it on these secure networks it is important that they remain O(1) or at most O(n) time complexity, which for these kinds of applications is often totally enough. (eg. if (the message is signed by the 'owner') { send the funds } else { throw })

JasoonS 9y ago

Another interesting use case is for supply chain management, since the history of a interactions relating product can be documented in a secure manner Eg. you can buy a nike shoe that you can cryptographically validate that it was signed off by Nike, who made it, when they made it, when it was shipped, and even how much each of these parties got paid for their service. (Take a listen here: https://media.consensys.net/state-change-44-shining-a-light-on-slavery-eeae67594af3 https://media.consensys.net/state-change-44-shining-a-light-...)