Accept a credential from a contract or a backend.

npm install @redact/verify

import { verify, Registry } from "@redact/verify";

// offchain: verify a proof object presented by the holder
const result = await verify(proof, {
  origin:    "instagram.com",
  predicate: "follower_count >= 100000",
  maxAge:    "7d",
  notaries:  ["redact-tee-01", "redact-tee-02"],
});

if (!result.valid) throw new Error(result.reason);
admit(result.holder);

// onchain read: check an existing credential by holder
const registry = new Registry({ chain: "robinhood" });
const cred = await registry.get(holder, {
  origin: "instagram.com", predicate: "follower_count >= 100000"
});

interface IRedactRegistry {
  function has(
    address holder,
    bytes32 originHash,
    bytes32 predicateHash,
    uint64  maxAge
  ) external view returns (bool);
}

contract Drop {
  IRedactRegistry constant REDACT = IRedactRegistry(0x5f1D...);
  bytes32 constant ORIGIN = keccak256("instagram.com");
  bytes32 constant PRED   = keccak256("follower_count>=100000");

  function mint() external {
    require(REDACT.has(msg.sender, ORIGIN, PRED, 7 days), "not eligible");
    _mint(msg.sender);
  }
}