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