62 lines
1.8 KiB
TypeScript
62 lines
1.8 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 { gen_pow } from "@mcaptcha/pow-wasm";
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import * as p from "@mcaptcha/pow_sha256-polyfill";
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import { WasmWork, 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<WasmWork> => {
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let proof: WasmWork = null;
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if (WasmSupported) {
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const proofString = gen_pow(
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config.salt,
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config.string,
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config.difficulty_factor
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);
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proof = JSON.parse(proofString);
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} else {
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console.log("WASM unsupported, expect delay during proof generation");
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proof = await p.generate_work(
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config.salt,
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config.string,
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config.difficulty_factor
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);
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}
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return proof;
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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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