ERC820a Pseudo-introspection Registry Contract

Universal registry smart contract where any address (contract or regular account) can register which interface it supports and which smart contract is responsible for its implementation.

ℹ️ ERC820a has superseded ERC820. ℹ️
ERC820a fixes the incompatibility in the ERC165 logic which was introduced by the Solidty 0.5 update.
Have a look at the official announcement, and the comments about the bug and the fix.
Apart from this fix, ERC820a is functionally equivalent to ERC820.

⚠️ ERC820a MUST be used in lieu of ERC820. ⚠️

Proposal

The official proposal can be found at: eips.ethereum.org/EIPS/eip-820a.

ERC820a Registry

This repository contains the official implementation of the ERC820a registry as defined in the standard.

The address of the registry on all chains is:

0x820a4875aA7900995D6f4ed84ab66651dd582aef

ERC820a Implementer

The ERC820a implementer interface is the interface any contract MUST implement if said contract implements an interface on behalf of another address via ERC820a.

Compilation & Verification

⚠️ The solc compiler version 0.5.3+commit.10d17f24 must be present on the build machine. (More info on installing solc.)

The registry can be compiled from the source code using:

npm run build

This will write the json artifacts for the registry in the artifacts folder and the standard output in the build folder.

Verification

The address of the account creating the registry, the address of the registry and the raw signed transaction can be generated with:

$ npm run info

> node js/info.js

RawTx:  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
Sender:  0x66bBAD577a9e2a9D7BD765562F9Ed657AD36C6d9
Contract: 0x820a4875aA7900995D6f4ed84ab66651dd582aef

Those values can be compared with the values in the ERC820a standard.

Metadata

The metadata---for the registry only---can be extrated using:

node scripts/extract_metadata.js

This metadata can also be compared with the formated version in the ERC820a standard.

Vanity address

The vanity address of the registry---starting with 0x820a---has been generated using the scripts/vanitygen.sh and scripts/vanitygen-info.js scripts.

Authors

• Jordi Baylina @jbaylina
• Jacques Dafflon @0xjac

License

The ERC820a registry is part of the ERC820a standard and is therefore in the public domain via CC0.

The authors waive all copyright and related or neighboring rights for the rest of this repository's content via CC0. A copy of the CC0 waiver is included in the LICENSE file.