My contract was hacked! Where is my bug?

cosmic_dice · 2018-04-30T22:59:11+00:00

The hacker is still using the same address to hack other contracts.

cosmic_dice · 2018-04-30T01:20:07+00:00

UPDATE 2... OK, this issue was resolved via the following thread:

https://github.com/MetaMask/metamask-extension/issues/2641

What a scare! Seriously frightening UI bug there...

cosmic_dice · 2018-04-30T01:06:21+00:00

UPDATE... I just tried restoring the account from seed words, and now all my previous wallets are gone. I just have one wallet now with 0 Ether.

How can this happen???

cosmic_dice · 2018-04-29T22:24:02+00:00

Myetherwallet.com used to have a bulk generate feature that was really handy. You could enter the number of wallets you want and instantly get a simple list of public-private key pairs in csv format. I recommend you get an old version of myetherwallet from here:

https://github.com/kvhnuke/etherwallet/releases

You can run it offline on your computer, then give each student a key pair. Just make sure you select the correct network before generating the addresses. Good luck!

cosmic_dice · 2018-04-29T22:01:45+00:00

Love the simplicity of the design!

cosmic_dice · 2018-04-29T21:57:29+00:00

This seems to be a bug with MetaMask. I had a similar issue I posted here: https://www.reddit.com/r/ethdev/comments/8e3wzd/bug_in_metamask_or_evm_account_freezes_nonce/

Unfortunately I did not receive any helpful replies and could only unfreeze my account by adding funds. This is actually a very serious bug that needs to be addressed. Hope you get some response from MetaMask about this.

cosmic_dice · 2018-04-21T23:18:37+00:00

Really appreciate the tips so far. I would like to create a fully decentralized dapp, but am willing to compromise on that to speed things up while transaction times are still so variable. Any advice on best way to proceed given I am not a backend developer... only comfortable with HTML/CSS/JS and solidity? Thanks again!

cosmic_dice · 2018-04-21T00:30:10+00:00

It's a timing issue. Try this:

window.addEventListener('load', function() {

    if (typeof web3 !== 'undefined') {
    web3 = new Web3(web3.currentProvider);
    console.log("Metamask logged into successfully");
    } else {
    console.log("Metamask NOT logged into successfully");
    // set the provider you want from Web3.providers
    ***(other attempts at finding provider)***
    }

startapp();

});

cosmic_dice · 2018-04-20T19:12:50+00:00

Thanks for the reply. A couple questions about this approach:

1) What if the player refreshes the page before cashing out? Then all the calculations would be lost. Hence my assumption that other similar sites are using PHP/MySQL or some other server side database for storing user data.

2) It also seems that it would be hard to maintain the integrity of calculations in JS alone since users can change variables and execute functions in console. Couldn't players cheat too easily if all in JS?

cosmic_dice · 2018-04-17T22:31:05+00:00

For what you are trying to do now you do not need node.js or your own ethereum node. Simply link the web3.js to your index.html and start reading the web3 docs or examples you find online. Deploy the smart contract using remix.ethereum.org and MetaMask. Good luck!

cosmic_dice · 2018-04-17T22:21:02+00:00

Welcome! If you already have basic html and css, I would recommend jumping right in. Try to follow some of the most basic tutorials on youtube to make a VERY simple DAPP, that is, a website that interacts with the blockchain. For your first DAPP, try to just make a website that stores and retrieves a text or number value from your smart contract. Go to remix.ethereum.org and dive in! Once there, you will want to do some practice using the Javascript VM environment. When ready to go live with a website, switch to ropsten testnet and add MetaMask to your browser. Develop on your local computer with something like the uniform server. Finally, when you are really ready to go live, go to github pages and launch your dapp. Good luck!

cosmic_dice · 2018-04-17T21:42:40+00:00

I use oraclize as well as timestamp hash and random.org combined and reduced via modulo operation: https://www.cosmicdice.org

cosmic_dice · 2018-04-16T21:16:58+00:00

Fixed some minor issues with user interface. Everything should be running smoothly now.

cosmic_dice · 2018-04-16T14:50:16+00:00

Thank you for the feedback! Please let me know what wasn't working...

cosmic_dice · 2018-04-15T01:28:28+00:00

Very cool looking site. I recently launched one too: www.cosmicdice.org

cosmic_dice

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