import { concat, uint64be } from '../lib/buffer_utils.js'; import checkIvLength from '../lib/check_iv_length.js'; import checkCekLength from './check_cek_length.js'; import crypto, { isCryptoKey } from './webcrypto.js'; import { checkEncCryptoKey } from '../lib/crypto_key.js'; import invalidKeyInput from '../lib/invalid_key_input.js'; import { JOSENotSupported } from '../util/errors.js'; import { types } from './is_key_like.js'; async function cbcEncrypt(enc, plaintext, cek, iv, aad) { if (!(cek instanceof Uint8Array)) { throw new TypeError(invalidKeyInput(cek, 'Uint8Array')); } const keySize = parseInt(enc.slice(1, 4), 10); const encKey = await crypto.subtle.importKey('raw', cek.subarray(keySize >> 3), 'AES-CBC', false, ['encrypt']); const macKey = await crypto.subtle.importKey('raw', cek.subarray(0, keySize >> 3), { hash: `SHA-${keySize << 1}`, name: 'HMAC', }, false, ['sign']); const ciphertext = new Uint8Array(await crypto.subtle.encrypt({ iv, name: 'AES-CBC', }, encKey, plaintext)); const macData = concat(aad, iv, ciphertext, uint64be(aad.length << 3)); const tag = new Uint8Array((await crypto.subtle.sign('HMAC', macKey, macData)).slice(0, keySize >> 3)); return { ciphertext, tag }; } async function gcmEncrypt(enc, plaintext, cek, iv, aad) { let encKey; if (cek instanceof Uint8Array) { encKey = await crypto.subtle.importKey('raw', cek, 'AES-GCM', false, ['encrypt']); } else { checkEncCryptoKey(cek, enc, 'encrypt'); encKey = cek; } const encrypted = new Uint8Array(await crypto.subtle.encrypt({ additionalData: aad, iv, name: 'AES-GCM', tagLength: 128, }, encKey, plaintext)); const tag = encrypted.slice(-16); const ciphertext = encrypted.slice(0, -16); return { ciphertext, tag }; } const encrypt = async (enc, plaintext, cek, iv, aad) => { if (!isCryptoKey(cek) && !(cek instanceof Uint8Array)) { throw new TypeError(invalidKeyInput(cek, ...types, 'Uint8Array')); } checkIvLength(enc, iv); switch (enc) { case 'A128CBC-HS256': case 'A192CBC-HS384': case 'A256CBC-HS512': if (cek instanceof Uint8Array) checkCekLength(cek, parseInt(enc.slice(-3), 10)); return cbcEncrypt(enc, plaintext, cek, iv, aad); case 'A128GCM': case 'A192GCM': case 'A256GCM': if (cek instanceof Uint8Array) checkCekLength(cek, parseInt(enc.slice(1, 4), 10)); return gcmEncrypt(enc, plaintext, cek, iv, aad); default: throw new JOSENotSupported('Unsupported JWE Content Encryption Algorithm'); } }; export default encrypt;