gen_nice_cosmos_address.ts

import { toUtf8, fromBech32, toAscii, toBech32 } from '@cosmjs/encoding';
import { sha256 } from '@cosmjs/crypto';
import { Uint64 } from '@cosmjs/math';
import { CosmWasmClient } from '@cosmjs/cosmwasm-stargate';

function increaseBytes(bytes: Uint8Array) {
  for (let i = bytes.length - 1; i >= 0; --i) {
    if (bytes[i] === 255) {
      bytes[i] = 0;
    } else {
      bytes[i]++;
      break;
    }
  }
}

function toUint64(int: number): Uint8Array {
  return Uint64.fromNumber(int).toBytesBigEndian();
}

(async () => {
  const prefix = 'orai';
  const msg = {};
  const saltLength = 8;
  const codeId = 1;
  const creator = 'orai1xxx';
  // get from code id
  const client = await CosmWasmClient.connect('https://rpc.orai.io');
  const res = await client.getCodeDetails(codeId);
  const checksum = Buffer.from(res.checksum, 'hex');
  const moduleData = sha256(toAscii('module'));
  const wasmData = toAscii('wasm');
  const checksumLengthData = toUint64(checksum.length);

  const saltLengthData = toUint64(saltLength);

  const msgData = toUtf8(JSON.stringify(msg));
  const msgLengthData = toUint64(msgData.length);

  const creatorData = fromBech32(creator).data;
  const creatorLengthData = toUint64(creatorData.length);

  const prepareData = new Uint8Array([
    ...moduleData,
    ...wasmData,
    0x00,
    ...checksumLengthData,
    ...checksum,
    ...creatorLengthData,
    ...creatorData,
    ...saltLengthData,
  ]);

  const key = Buffer.from([
    ...prepareData,
    ...new Uint8Array(saltLength), // salt buffer
    ...msgLengthData,
    ...msgData,
  ]);

  const saltIndex = prepareData.length;
  const salt = key.subarray(saltIndex, saltIndex + saltLength);

  while (true) {
    // change salt part
    increaseBytes(salt);

    const addressData = sha256(key);
    const address = toBech32(prefix, addressData);

    // at least 9999 at the end
    if (address.match(/9{4,}$/))
      console.log(address, 'salt', salt.toString('hex'));
  }
})();