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- "use strict";
- Object.defineProperty(exports, "__esModule", { value: true });
- const crypto_1 = require("crypto");
- const check_iv_length_js_1 = require("../lib/check_iv_length.js");
- const check_cek_length_js_1 = require("./check_cek_length.js");
- const buffer_utils_js_1 = require("../lib/buffer_utils.js");
- const errors_js_1 = require("../util/errors.js");
- const timing_safe_equal_js_1 = require("./timing_safe_equal.js");
- const cbc_tag_js_1 = require("./cbc_tag.js");
- const webcrypto_js_1 = require("./webcrypto.js");
- const crypto_key_js_1 = require("../lib/crypto_key.js");
- const is_key_object_js_1 = require("./is_key_object.js");
- const invalid_key_input_js_1 = require("../lib/invalid_key_input.js");
- const ciphers_js_1 = require("./ciphers.js");
- const is_key_like_js_1 = require("./is_key_like.js");
- function cbcDecrypt(enc, cek, ciphertext, iv, tag, aad) {
- const keySize = parseInt(enc.slice(1, 4), 10);
- if ((0, is_key_object_js_1.default)(cek)) {
- cek = cek.export();
- }
- const encKey = cek.subarray(keySize >> 3);
- const macKey = cek.subarray(0, keySize >> 3);
- const macSize = parseInt(enc.slice(-3), 10);
- const algorithm = `aes-${keySize}-cbc`;
- if (!(0, ciphers_js_1.default)(algorithm)) {
- throw new errors_js_1.JOSENotSupported(`alg ${enc} is not supported by your javascript runtime`);
- }
- const expectedTag = (0, cbc_tag_js_1.default)(aad, iv, ciphertext, macSize, macKey, keySize);
- let macCheckPassed;
- try {
- macCheckPassed = (0, timing_safe_equal_js_1.default)(tag, expectedTag);
- }
- catch {
- }
- if (!macCheckPassed) {
- throw new errors_js_1.JWEDecryptionFailed();
- }
- let plaintext;
- try {
- const decipher = (0, crypto_1.createDecipheriv)(algorithm, encKey, iv);
- plaintext = (0, buffer_utils_js_1.concat)(decipher.update(ciphertext), decipher.final());
- }
- catch {
- }
- if (!plaintext) {
- throw new errors_js_1.JWEDecryptionFailed();
- }
- return plaintext;
- }
- function gcmDecrypt(enc, cek, ciphertext, iv, tag, aad) {
- const keySize = parseInt(enc.slice(1, 4), 10);
- const algorithm = `aes-${keySize}-gcm`;
- if (!(0, ciphers_js_1.default)(algorithm)) {
- throw new errors_js_1.JOSENotSupported(`alg ${enc} is not supported by your javascript runtime`);
- }
- try {
- const decipher = (0, crypto_1.createDecipheriv)(algorithm, cek, iv, { authTagLength: 16 });
- decipher.setAuthTag(tag);
- if (aad.byteLength) {
- decipher.setAAD(aad, { plaintextLength: ciphertext.length });
- }
- const plaintext = decipher.update(ciphertext);
- decipher.final();
- return plaintext;
- }
- catch {
- throw new errors_js_1.JWEDecryptionFailed();
- }
- }
- const decrypt = (enc, cek, ciphertext, iv, tag, aad) => {
- let key;
- if ((0, webcrypto_js_1.isCryptoKey)(cek)) {
- (0, crypto_key_js_1.checkEncCryptoKey)(cek, enc, 'decrypt');
- key = crypto_1.KeyObject.from(cek);
- }
- else if (cek instanceof Uint8Array || (0, is_key_object_js_1.default)(cek)) {
- key = cek;
- }
- else {
- throw new TypeError((0, invalid_key_input_js_1.default)(cek, ...is_key_like_js_1.types, 'Uint8Array'));
- }
- (0, check_cek_length_js_1.default)(enc, key);
- (0, check_iv_length_js_1.default)(enc, iv);
- switch (enc) {
- case 'A128CBC-HS256':
- case 'A192CBC-HS384':
- case 'A256CBC-HS512':
- return cbcDecrypt(enc, key, ciphertext, iv, tag, aad);
- case 'A128GCM':
- case 'A192GCM':
- case 'A256GCM':
- return gcmDecrypt(enc, key, ciphertext, iv, tag, aad);
- default:
- throw new errors_js_1.JOSENotSupported('Unsupported JWE Content Encryption Algorithm');
- }
- };
- exports.default = decrypt;
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