61 lines
1.9 KiB
TypeScript
61 lines
1.9 KiB
TypeScript
/*
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* mCaptcha is a PoW based DoS protection software.
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* This is the frontend web component of the mCaptcha system
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* Copyright © 2021 Aravinth Manivnanan <realaravinth@batsense.net>.
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*
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* Use of this source code is governed by Apache 2.0 or MIT license.
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* You shoud have received a copy of MIT and Apache 2.0 along with
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* this program. If not, see <https://spdx.org/licenses/MIT.html> for
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* MIT or <http://www.apache.org/licenses/LICENSE-2.0> for Apache.
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*/
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import * as p from "@mcaptcha/pow_sha256-polyfill";
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import { PoWConfig } from "./types";
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/**
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* proove work
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* @param {PoWConfig} config - the proof-of-work configuration using which
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* work needs to be computed
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* */
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const prove = async (config: PoWConfig): Promise<number> => {
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console.log(`Wasm support says ${WasmSupported}`);
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let duration: number;
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if (WasmSupported) {
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const wasm = require("@mcaptcha/pow-wasm");
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const t0 = performance.now();
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wasm.gen_pow(config.salt, config.string, config.difficulty_factor);
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const t1 = performance.now();
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duration = t1 - t0;
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} else {
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console.log("WASM unsupported, expect delay during proof generation");
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const t0 = performance.now();
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await p.generate_work(config.salt, config.string, config.difficulty_factor);
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const t1 = performance.now();
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duration = t1 - t0;
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}
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return duration;
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};
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// credits: @jf-bastien on Stack Overflow
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// https://stackoverflow.com/questions/47879864/how-can-i-check-if-a-browser-supports-webassembly
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const WasmSupported = (() => {
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try {
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if (
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typeof WebAssembly === "object" &&
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typeof WebAssembly.instantiate === "function"
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) {
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const module = new WebAssembly.Module(
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Uint8Array.of(0x0, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00)
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);
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if (module instanceof WebAssembly.Module)
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return new WebAssembly.Instance(module) instanceof WebAssembly.Instance;
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}
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} catch (e) {
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console.error(e);
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}
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return false;
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})();
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export default prove;
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