node-opcua/node-opcua-crypto

// ---------------------------------------------------------------------------------------------------------------------
// node-opcua-crypto
// ---------------------------------------------------------------------------------------------------------------------
// Copyright (c) 2014-2022 - Etienne Rossignon - etienne.rossignon (at) gadz.org
// Copyright (c) 2022-2024 - Sterfive.com
// ---------------------------------------------------------------------------------------------------------------------
//
// This  project is licensed under the terms of the MIT license.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
// documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so,  subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
// Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
// WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// ---------------------------------------------------------------------------------------------------------------------
import { getCrypto } from "./_crypto.js";

// https://stackoverflow.com/questions/56807959/generate-public-key-from-private-key-using-webcrypto-api
export async function buildPublicKey(privateKey: CryptoKey): Promise<CryptoKey> {
    const crypto = getCrypto();

    // export private key to JWK
    const jwk = await crypto.subtle.exportKey("jwk", privateKey);

    // remove private data from JWK
    delete jwk.d;
    delete jwk.dp;
    delete jwk.dq;
    delete jwk.q;
    delete jwk.qi;
    jwk.key_ops = [
        "encrypt",
        "sign",
        // "wrapKey"
    ];

    // import public key
    // const publicKey = await crypto.subtle.importKey("jwk", jwk, { name: "RSA-OAEP", hash: { name: "SHA-256" } }, true, [
    const publicKey = await crypto.subtle.importKey("jwk", jwk, { name: "RSASSA-PKCS1-v1_5", hash: { name: "SHA-256" } }, true, [
        //   "encrypt",
        //     "sign",
        // "wrapKey",
    ]);

    return publicKey;
}