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