52 lines
2.0 KiB
Plaintext
52 lines
2.0 KiB
Plaintext
import random from './random.js';
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import { p2s as concatSalt } from '../lib/buffer_utils.js';
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import { encode as base64url } from './base64url.js';
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import { wrap, unwrap } from './aeskw.js';
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import checkP2s from '../lib/check_p2s.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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function getCryptoKey(key, alg) {
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if (key instanceof Uint8Array) {
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return crypto.subtle.importKey('raw', key, 'PBKDF2', false, ['deriveBits']);
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}
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if (isCryptoKey(key)) {
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checkEncCryptoKey(key, alg, 'deriveBits', 'deriveKey');
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return key;
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}
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throw new TypeError(invalidKeyInput(key, ...types, 'Uint8Array'));
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}
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async function deriveKey(p2s, alg, p2c, key) {
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checkP2s(p2s);
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const salt = concatSalt(alg, p2s);
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const keylen = parseInt(alg.slice(13, 16), 10);
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const subtleAlg = {
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hash: `SHA-${alg.slice(8, 11)}`,
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iterations: p2c,
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name: 'PBKDF2',
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salt,
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};
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const wrapAlg = {
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length: keylen,
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name: 'AES-KW',
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};
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const cryptoKey = await getCryptoKey(key, alg);
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if (cryptoKey.usages.includes('deriveBits')) {
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return new Uint8Array(await crypto.subtle.deriveBits(subtleAlg, cryptoKey, keylen));
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}
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if (cryptoKey.usages.includes('deriveKey')) {
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return crypto.subtle.deriveKey(subtleAlg, cryptoKey, wrapAlg, false, ['wrapKey', 'unwrapKey']);
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}
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throw new TypeError('PBKDF2 key "usages" must include "deriveBits" or "deriveKey"');
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}
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export const encrypt = async (alg, key, cek, p2c = 2048, p2s = random(new Uint8Array(16))) => {
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const derived = await deriveKey(p2s, alg, p2c, key);
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const encryptedKey = await wrap(alg.slice(-6), derived, cek);
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return { encryptedKey, p2c, p2s: base64url(p2s) };
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};
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export const decrypt = async (alg, key, encryptedKey, p2c, p2s) => {
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const derived = await deriveKey(p2s, alg, p2c, key);
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return unwrap(alg.slice(-6), derived, encryptedKey);
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};
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