100 thoughts on “Ethereum in Depth: Smart Contracts – Part 1: What is a Smart Contract?”

  1. How can someone down vote such an awesome explanation of smart contracts, the best i have seen anywhere on the internet. Like everywhere else, we have morons down voting such awesome videos.

  2. How would you define the conditions of a natural diaster into the smart contract? Also is it easy for the average person to see and understand the terms inputed into the code of the smart contract? Is it possible that people could still be taken advantage of if they dont know whats in the smart contract?

  3. man i like the second example alot.. easy to understand.
    once the money has been put into the contract the owner cant take it out.

    It should be possible to use this technology for stuff like presidential elections or representatives. This way no one should be able to modify it for their own benefits. and we would be able to verify every vote.

  4. First, bravo on delving into smart contract use case. Finally someone that doesn't belabor the fckn tech specs we all know already and focuses on real use case which I think is where the real conversation should tack. So many people have a hard on for the technology, but don't realize most industries simply don't give a fuck about decentralization. I totally see financial services as a true marketplace, but social media??? nah… oversimplifying the reason people use Social Media in the first place. Anywho, one thing i'm unclear on is hosting an app on ETH network. Are we talking about like running webservers on this thing or what? How can we expect good performance here?

  5. The video helped me a lot in understanding smart contracts. I am a ruby and js developer and this Ethereum thing is very fascinating in terms of future opportunities for developers and the way web is functioning nowadays. Thanks for the great explanation!

  6. Awesome content with an incredible explanation of it all! Thanks so much, bro. I'm a little nervous about the "internet of things" concept though considering the health affects the radiation can/will have on us.

  7. Thank you for your great videos on Ethereum! You are really good at explaining. The only "problem" that I see is that the average person won't understand the code and then again a third party is needed so that the code can be trusted…

  8. Thanks for this video. I think the idea is great.
    Let's say someone create a decentralized facebook and a decentralized google that become number one in their field. Would etherium be able to handle the big amount of data and big number users?

  9. Kevin after watching your video i thought to myself why cant a smart contract be implemented in a lending investment platform to make it alot more sustainable and alot less risky. I dont think it would remove all of the risk but i wonder if it could be implemented on a lending platform that has a erc20 token like Falconcoin? If you think something like this is possible could you make a video explaining how it would possibly could be done?

  10. No Kevin Falcon Coin and other lending Platforms work like this, you register for an account then send the btc to your btc address and then purchase their coin and then lend or stake their coin to earn profits. If you lend your coin they use that to trade against bitcoins volatility and when they make profit they pay you a volatility interest payout of at least 1% or more. What Makes them risky is that they could close shop at any time and run off with everyones btc. I was wondering if a smart contract might be able to reduce the risk of capital theft by the owners so easily?

  11. Could you check out falconcoin.co they use hyperleger technology which kind of makes them unique in this space. I am trying to get them to implement a smart contract on the control of the value of our falconcoin and the investors total investment of falcoins price at the time of its 30 day average price. If they renig the falconcoin tokens are liquidated and converted to btc and sent to an offline wallet. What do you think?


  13. Can ethereum smart contracts be used to interact with other blockchains. For example if we were to use your payroll example but rather than dividing 10 eth among 5 people we decide to divide 10 dash by the 5 people but using smart contracts built on ether?

  14. Hey, I thought of writing you some suggestion from the Philippines.

    Listen to why I did not use a ETH wallet which was so popular and the best wallet. Here is my story:
    I had downloaded Etherium Wallet from the google play store and had opened the account with my email, number and informations and then had sent some BTC to the wallet from my coins.ph wallet. It was fine and I have actually liked the wallet. But then when I have tried to open the same wallet in my desktop, it says to scan the desktop wallets QR code with the mobile wallet QR code scanner. Guess what happen? I could find any option in my mobile wallet to scan the desktop's QR code ! There was no way I could combine the mobile and desktop wallet as there were no options. It gave me a sense that may be one of them were not the right wallet since I am suppose to be able tie these two same wallet which is my one and only Etherium Wallet. It gave me a notion that one of those wallet is a corrupt wallet and some bad thing may take place in the future. So I was concern. And then when I had scanned the computer wallet QR code with another wallet it says that the QR code is wrong. I scanned that address with many other friends Wallet and everywhere it showed that it was a wrong QR code. So, hopefully it will help you to find out why these thing happen. My thought was, probably someone had opened a fake ETH site where I had logged in, but then the wallet had suggested me that site though.

    I think, you should start a totally new wallet and tell all your subscribers to transfer there and stop using the old wallet and specially the desktop wallet. You too should be careful about your X developers. Keep a trust worthy developer who would not be compromised.

    I think, its the right time for ETH to shine in the crypto market as we all like ETH. Make sure that these kinds of hacking does not take place again and again. It may permantly boycott you as the customers will be afraid to use your wallet and so you will not have much investments then.

    Wish good luck to ETH. Hope my story will help you guys figure out the real problem and ETH becomes a great crypto.

  15. One Issue:

    1) There are no balances — they are merely implied by the transactional history. I understand that it helps to explain the blockchain in analogical terms, but people will understand it literally.

    In other words, only transactions are recorded, not balances. Yes, this is a semantic matter, but worth clearing up so people don't start perpetuating an inccuracy.

  16. I don't understand the part where you said smart contract is immutable. If so, how it is possible to change balance or other properties (list of authorized accounts etc…) in the contract ? And the fact that you can change the state of a contract (object) makes it no longer immutable.

  17. If you have a daunting error in your smart contract and you cannot modify it, can you at least remove it from the network?

  18. Hey Kevin, First of all thank you for the video. This gives me a very clear picture on Smart Contracts and its application.
    I Just had a question.
    What if I am a user and I sign up to be a part of the Blockchain by checking the contract and I know it is a executed Smart Contract so i will be paid if things match as per the contract. But what if there is no balance in the Smart Contract? How will I get paid even if the instance match the criteria of smart contract.
    You can co-relate this to an example of me signing up with an insurance company.

    P.S: If anyone else has an answer, please feel free to respond.

  19. Another Question: When we are working through Smart Contracts, do we still have Miners into the Block Chain to verify every change or the Contract is sufficient. So in your Payroll example, would we have miners checking on the transactions and validating it? If yes, who would they be?

  20. Great video! I have a question though. You said the components of the smart contract paryroll example (code) and you said nobody has the power to change this even the person who wrote the smart contract. But I have been reading articles about bugs and security holes that a hacker tried to drain $50million ether while developers tried to come up with a solution.

  21. Dylyver, a ride sharing and an on demand delivery company, will launch its ICO campaign on May 16. Join our initiative, participate in the bounty program and earn referral tokens from all the people that you invite.

  22. Great video! I've often heard that ETH contracts are different from BTC smart contracts in that ETH contracts "loop." Does that simply mean that ETH contracts don't expire and can be repeatedly queried as opposed to BTC smart contracts, once the conditional statements are fulfilled, it expires?

  23. i dont understand the whole notion of no one can alter… of course if i am the creator of a contract and i release a new version where i actually steal your data. So centralised or decentralised; the case people build that we are taking away control from one company doesnt make sense at all with all these ICOs popping up on etherium. The ICO team are centralised so what if the application is decentralised.

  24. Awesome! Thanks man, you explained it so well. Well done! Have you heard about SciDex? They have a promising project, been looking forward to it.

  25. So, a smart contract is a delayed transaction waiting for a some event to trigger. If I'm wrong, please correct me.

  26. Please do check our smart contract based coffee supply chain implementation : https://github.com/imperialsoftech/coffee-supplychain-ethereum

  27. Dear sir,
    Your knowledge for smart contracts, etherneum,blockchain realted is very enormous and appreciable ,i do need a guide to have a live conversation over this topic because i m developing a smart contract it will be a big help if we can connect
    Love your work!!

  28. Very interesting Kevin, I am about to build a new one, therefore, I need your contact, via skype, email, or mobile apps in order I can have your advise or services to decorate it well and healthier. Many smart contracts and features you have explained are matching the draft that my team are aiming to. Waiting your reply soon!

  29. how can the sys/protocol (eth, in this case) of a smart contract assure this unbreakable stability of the code away of bad hacking? is it possible to explain it in a easy understandable way/metaphor? what "magic" prevents it of being cracked ?

  30. Dear Kevin, congratulations with the excellent presentations. Listening to your different videos I have some immediate questions.1. You state that the difference between account and smart contract is the fact that the smart contract does not need a private key to be active. You also stated that a smart contract needs to be developed and debugged by its author and I read elsewhere that only the author can deactivate the smart contract. Does that not mean that for editing purposes a private key is needed?2. The immutability of the block-chain is also applied on the smart contract. But if the block-chain is containing transaction information (and not the accounts of individuals) are instances of smart contracts than put in blocks of a separate block-chain?3. I miss the notion of object as blueprint of Accounts and Smart Contracts. Where are they kept? Accounts are instantiations of an Account object, and the smart contract from a smart contract object. Are these blueprints not put on a blockchain in order to make them immutable and distributed?Thanks in advance for some clarification.Stefan

  31. Excellent job. I started following Vitalik Buterin and I really think that because of dapps and smart contracts, Ethereum will eventually take over Bitcoin. Processing transactions are hell of a lot faster on the Ethereum network. I am looking forward to watching Part 2

  32. In the first example of distributing ethers equally among 5 employees, what will happen if the no of employees is changed. I mean, since this contract is deployed in the Blockchain, hence immutable.. So, I can't add/delete account addresses of the employees in the existing contract..So, Should the administrator needs to write another new contract to be deployed in the Blockchain? If it so, then every time some changes occurs in the real world, the contract needs to get modified to reflect the fact..Then how does the automation work?

  33. hey how long woud it take you to write a smart contract like in your example of distrubiting ETH to 5 accounts? how bright is the future for BTC smart contracts? will there be any real need to uses the ETH network and their contracts?

  34. You can terminate a smart contract:

    function close() public
    Calling close() deletes the contract, returning the funds to owner.
    EDIT: is that a didgeridoo in the corner?

  35. What if the stats company goes bust or shuts down the api? Or they decide to reclassify what an earthquake is, like say anything below 5 is a tremor not a quake?

  36. Let have a glance about how smart contract used in Dapps .To know more about smart contract


  37. Brilliant way to educate on the concept of smart contract. Really simple definition that everyone could easily understand. Hat off to you for your excellent work!

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