43 lines
1.7 KiB
Plaintext
43 lines
1.7 KiB
Plaintext
import { encode as b64u } from '../util/base64url.js';
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import * as aeskw from './aeskw.js';
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import { checkEncCryptoKey } from './crypto_key.js';
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import { concat, encode } from './buffer_utils.js';
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import { JWEInvalid } from '../util/errors.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, [
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'deriveBits',
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]);
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}
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checkEncCryptoKey(key, alg, 'deriveBits');
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return key;
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}
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const concatSalt = (alg, p2sInput) => concat(encode(alg), Uint8Array.of(0x00), p2sInput);
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async function deriveKey(p2s, alg, p2c, key) {
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if (!(p2s instanceof Uint8Array) || p2s.length < 8) {
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throw new JWEInvalid('PBES2 Salt Input must be 8 or more octets');
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}
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if (!Number.isSafeInteger(p2c) || Math.sign(p2c) !== 1) {
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throw new JWEInvalid('PBES2 Count Input must be a positive integer');
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}
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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 cryptoKey = await getCryptoKey(key, alg);
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return new Uint8Array(await crypto.subtle.deriveBits(subtleAlg, cryptoKey, keylen));
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}
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export async function wrap(alg, key, cek, p2c = 2048, p2s = crypto.getRandomValues(new Uint8Array(16))) {
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const derived = await deriveKey(p2s, alg, p2c, key);
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const encryptedKey = await aeskw.wrap(alg.slice(-6), derived, cek);
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return { encryptedKey, p2c, p2s: b64u(p2s) };
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}
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export async function unwrap(alg, key, encryptedKey, p2c, p2s) {
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const derived = await deriveKey(p2s, alg, p2c, key);
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return aeskw.unwrap(alg.slice(-6), derived, encryptedKey);
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}
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