mCaptcha/templates/widget/prove.ts
2021-12-08 14:52:06 +05:30

61 lines
1.8 KiB
TypeScript

/*
* mCaptcha is a PoW based DoS protection software.
* This is the frontend web component of the mCaptcha system
* Copyright © 2021 Aravinth Manivnanan <realaravinth@batsense.net>.
*
* Use of this source code is governed by Apache 2.0 or MIT license.
* You shoud have received a copy of MIT and Apache 2.0 along with
* this program. If not, see <https://spdx.org/licenses/MIT.html> for
* MIT or <http://www.apache.org/licenses/LICENSE-2.0> for Apache.
*/
import { gen_pow } from "@mcaptcha/pow-wasm";
import * as p from "@mcaptcha/pow_sha256-polyfill";
import { WasmWork, PoWConfig } from "./types";
/**
* proove work
* @param {PoWConfig} config - the proof-of-work configuration using which
* work needs to be computed
* */
const prove = async (config: PoWConfig): Promise<WasmWork> => {
let proof: WasmWork = null;
if (WasmSupported) {
const proofString = gen_pow(
config.salt,
config.string,
config.difficulty_factor
);
proof = JSON.parse(proofString);
} else {
console.log("WASM unsupported, expect delay during proof generation");
proof = await p.generate_work(
config.salt,
config.string,
config.difficulty_factor
);
}
return proof;
};
// credits: @jf-bastien on Stack Overflow
// https://stackoverflow.com/questions/47879864/how-can-i-check-if-a-browser-supports-webassembly
const WasmSupported = (() => {
try {
if (
typeof WebAssembly === "object" &&
typeof WebAssembly.instantiate === "function"
) {
const module = new WebAssembly.Module(
Uint8Array.of(0x0, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00)
);
if (module instanceof WebAssembly.Module)
return new WebAssembly.Instance(module) instanceof WebAssembly.Instance;
}
} catch (e) {
console.error(e);
}
return false;
})();
export default prove;