Questions tagged [openzeppelin-contracts]

OpenZeppelin Contracts is a library for secure smart contract development. It provides implementations of standards like ERC20 and ERC721 which you can deploy as-is or extend to suit your needs, as well as Solidity components to build custom contracts and more complex decentralized systems.

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Sign message with web3 and verify with openzeppelin-solidity ECDSA.sol

I'm trying to get a little example working with ECDSA.sol here: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/cryptography/ECDSA.sol This contract: Generate a random(...
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ERC721 how does tokenOfOwnerByIndex() list tokens owned by a user?

Per eip-721, there's an optional "enumeration extension". So what I did was I called balanceOf to get the number of tokens owned by the account and called tokenOfOwnerByIndex in a loop to get each ...
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ERC721Token super._mint calls addTokenTo from the top level implementation

Based on Shawn's answer, super._mint calls addTokenTo from the top level implementation (ERC721Token). How does this work? super._mint calls _mint from ERC721BasicToken reads line addTokenTo ...
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How to use function modifier to control contract function access right?

I deployed a ERC20Mintable token in truffle environment(the source file is ERC20Mintable.sol). The mint function is declared with onlyMinter modifer: contract ERC20Mintable is ERC20, MinterRole { ...