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import { concat, uint64be } from '../lib/buffer_utils.ts'
import type { DecryptFunction } from './interfaces.d.ts'import checkIvLength from '../lib/check_iv_length.ts'import checkCekLength from './check_cek_length.ts'import timingSafeEqual from './timing_safe_equal.ts'import { JOSENotSupported, JWEDecryptionFailed, JWEInvalid } from '../util/errors.ts'import crypto, { isCryptoKey } from './webcrypto.ts'import { checkEncCryptoKey } from '../lib/crypto_key.ts'import invalidKeyInput from '../lib/invalid_key_input.ts'import { types } from './is_key_like.ts'
async function cbcDecrypt(  enc: string,  cek: Uint8Array | CryptoKey,  ciphertext: Uint8Array,  iv: Uint8Array,  tag: Uint8Array,  aad: Uint8Array,) {  if (!(cek instanceof Uint8Array)) {    throw new TypeError(invalidKeyInput(cek, 'Uint8Array'))  }  const keySize = parseInt(enc.slice(1, 4), 10)  const encKey = await crypto.subtle.importKey(    'raw',    cek.subarray(keySize >> 3),    'AES-CBC',    false,    ['decrypt'],  )  const macKey = await crypto.subtle.importKey(    'raw',    cek.subarray(0, keySize >> 3),    {      hash: `SHA-${keySize << 1}`,      name: 'HMAC',    },    false,    ['sign'],  )
  const macData = concat(aad, iv, ciphertext, uint64be(aad.length << 3))  const expectedTag = new Uint8Array(    (await crypto.subtle.sign('HMAC', macKey, macData)).slice(0, keySize >> 3),  )
  let macCheckPassed!: boolean  try {    macCheckPassed = timingSafeEqual(tag, expectedTag)  } catch {    //  }  if (!macCheckPassed) {    throw new JWEDecryptionFailed()  }
  let plaintext!: Uint8Array  try {    plaintext = new Uint8Array(      await crypto.subtle.decrypt({ iv, name: 'AES-CBC' }, encKey, ciphertext),    )  } catch {    //  }  if (!plaintext) {    throw new JWEDecryptionFailed()  }
  return plaintext}
async function gcmDecrypt(  enc: string,  cek: Uint8Array | CryptoKey,  ciphertext: Uint8Array,  iv: Uint8Array,  tag: Uint8Array,  aad: Uint8Array,) {  let encKey: CryptoKey  if (cek instanceof Uint8Array) {    encKey = await crypto.subtle.importKey('raw', cek, 'AES-GCM', false, ['decrypt'])  } else {    checkEncCryptoKey(cek, enc, 'decrypt')    encKey = cek  }
  try {    return new Uint8Array(      await crypto.subtle.decrypt(        {          additionalData: aad,          iv,          name: 'AES-GCM',          tagLength: 128,        },        encKey,        concat(ciphertext, tag),      ),    )  } catch {    throw new JWEDecryptionFailed()  }}
const decrypt: DecryptFunction = async (  enc: string,  cek: unknown,  ciphertext: Uint8Array,  iv: Uint8Array | undefined,  tag: Uint8Array | undefined,  aad: Uint8Array,) => {  if (!isCryptoKey(cek) && !(cek instanceof Uint8Array)) {    throw new TypeError(invalidKeyInput(cek, ...types, 'Uint8Array'))  }
  if (!iv) {    throw new JWEInvalid('JWE Initialization Vector missing')  }  if (!tag) {    throw new JWEInvalid('JWE Authentication Tag missing')  }
  checkIvLength(enc, iv)
  switch (enc) {    case 'A128CBC-HS256':    case 'A192CBC-HS384':    case 'A256CBC-HS512':      if (cek instanceof Uint8Array) checkCekLength(cek, parseInt(enc.slice(-3), 10))      return cbcDecrypt(enc, cek, ciphertext, iv, tag, aad)    case 'A128GCM':    case 'A192GCM':    case 'A256GCM':      if (cek instanceof Uint8Array) checkCekLength(cek, parseInt(enc.slice(1, 4), 10))      return gcmDecrypt(enc, cek, ciphertext, iv, tag, aad)    default:      throw new JOSENotSupported('Unsupported JWE Content Encryption Algorithm')  }}
export default decrypt