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import { concat, uint64be } from './buffer_utils.js'; |
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import checkIvLength from './check_iv_length.js'; |
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import checkCekLength from './check_cek_length.js'; |
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import { checkEncCryptoKey } from './crypto_key.js'; |
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import invalidKeyInput from './invalid_key_input.js'; |
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import generateIv from './iv.js'; |
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import { JOSENotSupported } from '../util/errors.js'; |
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import { isCryptoKey } 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, iv }; |
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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, iv }; |
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} |
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export default 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, 'CryptoKey', 'KeyObject', 'Uint8Array', 'JSON Web Key')); |
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} |
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if (iv) { |
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checkIvLength(enc, iv); |
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} |
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else { |
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iv = generateIv(enc); |
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} |
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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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} |
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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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} |
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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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