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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, encoder } 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, ['deriveBits']); |
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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(encoder.encode(alg), new Uint8Array([0]), 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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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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