import * as aeskw from './aeskw.js';
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import * as ecdhes from './ecdhes.js';
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import * as pbes2kw from './pbes2kw.js';
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import * as rsaes from './rsaes.js';
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import { encode as b64u } from '../util/base64url.js';
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import { normalizeKey } from './normalize_key.js';
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import { JOSENotSupported, JWEInvalid } from '../util/errors.js';
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import { decodeBase64url } from './helpers.js';
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import { generateCek, cekLength } from './content_encryption.js';
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import { importJWK } from '../key/import.js';
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import { exportJWK } from '../key/export.js';
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import { isObject } from './type_checks.js';
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import { wrap as aesGcmKwWrap, unwrap as aesGcmKwUnwrap } from './aesgcmkw.js';
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import { assertCryptoKey } from './is_key_like.js';
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const unsupportedAlgHeader = 'Invalid or unsupported "alg" (JWE Algorithm) header value';
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function assertEncryptedKey(encryptedKey) {
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if (encryptedKey === undefined)
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throw new JWEInvalid('JWE Encrypted Key missing');
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}
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export async function decryptKeyManagement(alg, key, encryptedKey, joseHeader, options) {
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switch (alg) {
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case 'dir': {
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if (encryptedKey !== undefined)
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throw new JWEInvalid('Encountered unexpected JWE Encrypted Key');
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return key;
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}
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case 'ECDH-ES':
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if (encryptedKey !== undefined)
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throw new JWEInvalid('Encountered unexpected JWE Encrypted Key');
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case 'ECDH-ES+A128KW':
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case 'ECDH-ES+A192KW':
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case 'ECDH-ES+A256KW': {
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if (!isObject(joseHeader.epk))
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throw new JWEInvalid(`JOSE Header "epk" (Ephemeral Public Key) missing or invalid`);
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assertCryptoKey(key);
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if (!ecdhes.allowed(key))
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throw new JOSENotSupported('ECDH with the provided key is not allowed or not supported by your javascript runtime');
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const epk = await importJWK(joseHeader.epk, alg);
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assertCryptoKey(epk);
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let partyUInfo;
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let partyVInfo;
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if (joseHeader.apu !== undefined) {
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if (typeof joseHeader.apu !== 'string')
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throw new JWEInvalid(`JOSE Header "apu" (Agreement PartyUInfo) invalid`);
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partyUInfo = decodeBase64url(joseHeader.apu, 'apu', JWEInvalid);
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}
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if (joseHeader.apv !== undefined) {
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if (typeof joseHeader.apv !== 'string')
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throw new JWEInvalid(`JOSE Header "apv" (Agreement PartyVInfo) invalid`);
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partyVInfo = decodeBase64url(joseHeader.apv, 'apv', JWEInvalid);
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}
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const sharedSecret = await ecdhes.deriveKey(epk, key, alg === 'ECDH-ES' ? joseHeader.enc : alg, alg === 'ECDH-ES' ? cekLength(joseHeader.enc) : parseInt(alg.slice(-5, -2), 10), partyUInfo, partyVInfo);
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if (alg === 'ECDH-ES')
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return sharedSecret;
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assertEncryptedKey(encryptedKey);
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return aeskw.unwrap(alg.slice(-6), sharedSecret, encryptedKey);
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}
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case 'RSA-OAEP':
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case 'RSA-OAEP-256':
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case 'RSA-OAEP-384':
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case 'RSA-OAEP-512': {
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assertEncryptedKey(encryptedKey);
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assertCryptoKey(key);
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return rsaes.decrypt(alg, key, encryptedKey);
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}
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case 'PBES2-HS256+A128KW':
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case 'PBES2-HS384+A192KW':
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case 'PBES2-HS512+A256KW': {
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assertEncryptedKey(encryptedKey);
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if (typeof joseHeader.p2c !== 'number')
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throw new JWEInvalid(`JOSE Header "p2c" (PBES2 Count) missing or invalid`);
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const p2cLimit = options?.maxPBES2Count || 10_000;
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if (joseHeader.p2c > p2cLimit)
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throw new JWEInvalid(`JOSE Header "p2c" (PBES2 Count) out is of acceptable bounds`);
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if (typeof joseHeader.p2s !== 'string')
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throw new JWEInvalid(`JOSE Header "p2s" (PBES2 Salt) missing or invalid`);
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let p2s;
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p2s = decodeBase64url(joseHeader.p2s, 'p2s', JWEInvalid);
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return pbes2kw.unwrap(alg, key, encryptedKey, joseHeader.p2c, p2s);
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}
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case 'A128KW':
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case 'A192KW':
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case 'A256KW': {
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assertEncryptedKey(encryptedKey);
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return aeskw.unwrap(alg, key, encryptedKey);
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}
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case 'A128GCMKW':
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case 'A192GCMKW':
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case 'A256GCMKW': {
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assertEncryptedKey(encryptedKey);
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if (typeof joseHeader.iv !== 'string')
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throw new JWEInvalid(`JOSE Header "iv" (Initialization Vector) missing or invalid`);
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if (typeof joseHeader.tag !== 'string')
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throw new JWEInvalid(`JOSE Header "tag" (Authentication Tag) missing or invalid`);
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let iv;
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iv = decodeBase64url(joseHeader.iv, 'iv', JWEInvalid);
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let tag;
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tag = decodeBase64url(joseHeader.tag, 'tag', JWEInvalid);
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return aesGcmKwUnwrap(alg, key, encryptedKey, iv, tag);
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}
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default: {
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throw new JOSENotSupported(unsupportedAlgHeader);
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}
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}
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}
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export async function encryptKeyManagement(alg, enc, key, providedCek, providedParameters = {}) {
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let encryptedKey;
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let parameters;
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let cek;
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switch (alg) {
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case 'dir': {
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cek = key;
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break;
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}
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case 'ECDH-ES':
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case 'ECDH-ES+A128KW':
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case 'ECDH-ES+A192KW':
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case 'ECDH-ES+A256KW': {
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assertCryptoKey(key);
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if (!ecdhes.allowed(key)) {
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throw new JOSENotSupported('ECDH with the provided key is not allowed or not supported by your javascript runtime');
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}
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const { apu, apv } = providedParameters;
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let ephemeralKey;
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if (providedParameters.epk) {
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ephemeralKey = (await normalizeKey(providedParameters.epk, alg));
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}
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else {
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ephemeralKey = (await crypto.subtle.generateKey(key.algorithm, true, ['deriveBits'])).privateKey;
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}
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const { x, y, crv, kty } = await exportJWK(ephemeralKey);
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const sharedSecret = await ecdhes.deriveKey(key, ephemeralKey, alg === 'ECDH-ES' ? enc : alg, alg === 'ECDH-ES' ? cekLength(enc) : parseInt(alg.slice(-5, -2), 10), apu, apv);
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parameters = { epk: { x, crv, kty } };
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if (kty === 'EC')
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parameters.epk.y = y;
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if (apu)
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parameters.apu = b64u(apu);
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if (apv)
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parameters.apv = b64u(apv);
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if (alg === 'ECDH-ES') {
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cek = sharedSecret;
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break;
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}
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cek = providedCek || generateCek(enc);
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const kwAlg = alg.slice(-6);
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encryptedKey = await aeskw.wrap(kwAlg, sharedSecret, cek);
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break;
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}
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case 'RSA-OAEP':
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case 'RSA-OAEP-256':
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case 'RSA-OAEP-384':
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case 'RSA-OAEP-512': {
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cek = providedCek || generateCek(enc);
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assertCryptoKey(key);
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encryptedKey = await rsaes.encrypt(alg, key, cek);
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break;
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}
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case 'PBES2-HS256+A128KW':
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case 'PBES2-HS384+A192KW':
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case 'PBES2-HS512+A256KW': {
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cek = providedCek || generateCek(enc);
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const { p2c, p2s } = providedParameters;
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({ encryptedKey, ...parameters } = await pbes2kw.wrap(alg, key, cek, p2c, p2s));
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break;
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}
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case 'A128KW':
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case 'A192KW':
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case 'A256KW': {
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cek = providedCek || generateCek(enc);
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encryptedKey = await aeskw.wrap(alg, key, cek);
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break;
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}
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case 'A128GCMKW':
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case 'A192GCMKW':
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case 'A256GCMKW': {
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cek = providedCek || generateCek(enc);
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const { iv } = providedParameters;
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({ encryptedKey, ...parameters } = await aesGcmKwWrap(alg, key, cek, iv));
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break;
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}
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default: {
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throw new JOSENotSupported(unsupportedAlgHeader);
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}
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}
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return { cek, encryptedKey, parameters };
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}
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