ReCap

A Typescript implementation of ERC-5573 ReCap, enabling applications to express UCAN-style object capabilities using Sign In With Ethereum.

Installation

ReCap can be installed via npm:

npm -i siwe-recap

yarn:

yarn add siwe-recap

or package.json entry:

{
  "dependencies": {
    "siwe-recap": "0.0.2-alpha.0"
  }
}

Usage

ReCaps are designed to be used in conjunction with SIWE. They can be initialized and built as follows:

import { Recap } from 'siwe-recap';

const recap = new Recap();

recap.addAttenuation('https://example.com/my/resource', 'crud', 'read');
recap.addAttenuation('https://example.com/my/resource', 'crud', 'update', {
  maxTimes: 5,
});
recap.addProof('bagaaierasords4njcts6vs7qvdjfcvgnume4hqohf65zsfguprqphs3icwea');

console.log(recap.attenuations);
// {
//   "https://example.com/my/resource": {
//     "crud/read": [{}],
//     "crud/update": [{ maxTimes: 5 }]
//   }
// }

They can also be applied to or extracted from SIWE messages:

import { SiweMessage } from 'siwe';
import { Recap } from 'siwe-recap';

const siwe = new SiweMessage( ... );

// we can extract the recap while verifying that the statement in `siwe` matches
// the recap listed in `siwe`s resource list
const recap = Recap.extract_and_verify(siwe);

//
recap.addAttenuation('https://example.com/my/resource', 'crud', 'read');

// the new change will be merged into the existing recap in `siwe`
recap.add_to_siwe_messate(siwe);

Compilation

In order to generate the ECMAScript, CommonJS and TypeScript declaration files, run yarn compile.

Disclaimer

This package is still ALPHA software, bugs may exist and APIs may change in future. This library for has not yet undergone a formal security audit. We welcome continued feedback on the usability, architecture, and security of this implementation.