Store IPFS Hash as Bytes32 in Smart Contracts

Convert IPFS Hash to bytes32 format

If you are using bs58 version 4.0.0, do the following

const bs58 = require("bs58"); // version - `4.0.0`

const hash = "Qmc5gCcjYypU7y28oCALwfSvxCBskLuPKWpK4qpterKC7z";
const toBytes32 = (hash) => "0x" + bs58.decode(hash).slice(2).toString("hex");

console.log(toBytes32(hash)); // "0xcc2d976220820d023b7170f520d3490e811ed988ae3d6221474ee97e559b0361"

If you are using bs58 version 5.0.0, do the following

const bs58 = require("bs58"); // version - `5.0.0`

const hash = "Qmc5gCcjYypU7y28oCALwfSvxCBskLuPKWpK4qpterKC7z";
const toBytes32 = (hash) => {
  return (
    "0x" +
    bs58
      .decode(hash)
      .slice(2)
      .toString()
      .split(",")
      .map((x) => Number(x).toString(16))
      .map((x) => String(x).padStart(2, "0"))
      .join("")
  );
};

console.log(toBytes32(hash)); // "0xcc2d976220820d023b7170f520d3490e811ed988ae3d6221474ee97e559b0361"

Or you can instead use Buffer which is available in NodeJS environment

const bs58 = require("bs58"); // version - `5.0.0`

const hash = "Qmc5gCcjYypU7y28oCALwfSvxCBskLuPKWpK4qpterKC7z";
const toBytes32 = (hash) => {
  return "0x" + Buffer.from(bs58.decode(hash).slice(2)).toString("hex");
};

console.log(toBytes32(hash)); // "0xcc2d976220820d023b7170f520d3490e811ed988ae3d6221474ee97e559b0361"

Convert bytes32 to IPFS Hash format

If you are using bs58 version 5.0.0 or 4.0.0, do the following

const bs58 = require("bs58"); // version - `5.0.0` or `4.0.0`

const hashBytes32 = "0xcc2d976220820d023b7170f520d3490e811ed988ae3d6221474ee97e559b0361"
const fromBytes32 = (bytes32) => bs58.encode(Buffer.from('1220' + bytes32.slice(2), 'hex'))

console.log(fromBytes32(hashBytes32)) // "Qmc5gCcjYypU7y28oCALwfSvxCBskLuPKWpK4qpterKC7z"

Last Updated on May 21, 2022