47 lines
1.9 KiB
JavaScript
47 lines
1.9 KiB
JavaScript
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import { encoder, concat, uint32be, lengthAndInput, concatKdf } from '../lib/buffer_utils.js';
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import crypto, { isCryptoKey } from './webcrypto.js';
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import { checkEncCryptoKey } from '../lib/crypto_key.js';
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import invalidKeyInput from '../lib/invalid_key_input.js';
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import { types } from './is_key_like.js';
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export async function deriveKey(publicKey, privateKey, algorithm, keyLength, apu = new Uint8Array(0), apv = new Uint8Array(0)) {
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if (!isCryptoKey(publicKey)) {
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throw new TypeError(invalidKeyInput(publicKey, ...types));
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}
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checkEncCryptoKey(publicKey, 'ECDH');
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if (!isCryptoKey(privateKey)) {
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throw new TypeError(invalidKeyInput(privateKey, ...types));
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}
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checkEncCryptoKey(privateKey, 'ECDH', 'deriveBits');
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const value = concat(lengthAndInput(encoder.encode(algorithm)), lengthAndInput(apu), lengthAndInput(apv), uint32be(keyLength));
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let length;
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if (publicKey.algorithm.name === 'X25519') {
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length = 256;
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}
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else if (publicKey.algorithm.name === 'X448') {
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length = 448;
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}
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else {
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length =
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Math.ceil(parseInt(publicKey.algorithm.namedCurve.substr(-3), 10) / 8) << 3;
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}
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const sharedSecret = new Uint8Array(await crypto.subtle.deriveBits({
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name: publicKey.algorithm.name,
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public: publicKey,
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}, privateKey, length));
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return concatKdf(sharedSecret, keyLength, value);
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}
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export async function generateEpk(key) {
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if (!isCryptoKey(key)) {
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throw new TypeError(invalidKeyInput(key, ...types));
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}
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return crypto.subtle.generateKey(key.algorithm, true, ['deriveBits']);
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}
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export function ecdhAllowed(key) {
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if (!isCryptoKey(key)) {
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throw new TypeError(invalidKeyInput(key, ...types));
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}
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return (['P-256', 'P-384', 'P-521'].includes(key.algorithm.namedCurve) ||
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key.algorithm.name === 'X25519' ||
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key.algorithm.name === 'X448');
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}
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