73 lines
2.7 KiB
JavaScript
73 lines
2.7 KiB
JavaScript
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import { createCipheriv, KeyObject } from 'crypto';
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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 { concat } from '../lib/buffer_utils.js';
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import cbcTag from './cbc_tag.js';
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import { isCryptoKey } from './webcrypto.js';
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import { checkEncCryptoKey } from '../lib/crypto_key.js';
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import isKeyObject from './is_key_object.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 supported from './ciphers.js';
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import { types } from './is_key_like.js';
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function cbcEncrypt(enc, plaintext, cek, iv, aad) {
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const keySize = parseInt(enc.slice(1, 4), 10);
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if (isKeyObject(cek)) {
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cek = cek.export();
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}
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const encKey = cek.subarray(keySize >> 3);
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const macKey = cek.subarray(0, keySize >> 3);
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const algorithm = `aes-${keySize}-cbc`;
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if (!supported(algorithm)) {
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throw new JOSENotSupported(`alg ${enc} is not supported by your javascript runtime`);
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}
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const cipher = createCipheriv(algorithm, encKey, iv);
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const ciphertext = concat(cipher.update(plaintext), cipher.final());
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const macSize = parseInt(enc.slice(-3), 10);
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const tag = cbcTag(aad, iv, ciphertext, macSize, macKey, keySize);
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return { ciphertext, tag };
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}
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function gcmEncrypt(enc, plaintext, cek, iv, aad) {
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const keySize = parseInt(enc.slice(1, 4), 10);
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const algorithm = `aes-${keySize}-gcm`;
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if (!supported(algorithm)) {
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throw new JOSENotSupported(`alg ${enc} is not supported by your javascript runtime`);
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}
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const cipher = createCipheriv(algorithm, cek, iv, { authTagLength: 16 });
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if (aad.byteLength) {
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cipher.setAAD(aad, { plaintextLength: plaintext.length });
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}
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const ciphertext = cipher.update(plaintext);
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cipher.final();
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const tag = cipher.getAuthTag();
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return { ciphertext, tag };
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}
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const encrypt = (enc, plaintext, cek, iv, aad) => {
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let key;
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if (isCryptoKey(cek)) {
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checkEncCryptoKey(cek, enc, 'encrypt');
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key = KeyObject.from(cek);
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}
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else if (cek instanceof Uint8Array || isKeyObject(cek)) {
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key = cek;
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}
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else {
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throw new TypeError(invalidKeyInput(cek, ...types, 'Uint8Array'));
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}
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checkCekLength(enc, key);
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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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return cbcEncrypt(enc, plaintext, key, iv, aad);
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case 'A128GCM':
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case 'A192GCM':
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case 'A256GCM':
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return gcmEncrypt(enc, plaintext, key, 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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