U h@sZdZddlmZddlmZmZddlmZmZddl m Z ddl m Z Gdd d Z d S) z3 This module holds the CdnDecrypter utility class. )sha256)GetCdnFileRequestReuploadCdnFileRequest)CdnFileReuploadNeededCdnFile) AESModeCTR)CdnFileTamperedErrorc@s8eZdZdZddZeddZddZedd Zd S) CdnDecrypterz Used when downloading a file results in a 'FileCdnRedirect' to both prepare the redirect, decrypt the file as it downloads, and ensure the file hasn't been tampered. https://core.telegram.org/cdn cCs||_||_||_||_dS)a. Initializes the CDN decrypter. :param cdn_client: a client connected to a CDN. :param file_token: the token of the file to be used. :param cdn_aes: the AES CTR used to decrypt the file. :param cdn_file_hashes: the hashes the decrypted file must match. N)client file_tokencdn_aescdn_file_hashes)self cdn_clientr r rr@/tmp/pip-unpacked-wheel-c81u5j2r/telethon/crypto/cdndecrypter.py__init__s zCdnDecrypter.__init__cst|j|jddtdd}t||j||j}|t|j|jdj|jdj dIdH}t |t r|t |j|j dIdH|}n*|j|j|_|jd}||j|||fS)a9 Prepares a new CDN decrypter. :param client: a TelegramClient connected to the main servers. :param cdn_client: a new client connected to the CDN. :param cdn_redirect: the redirect file object that caused this call. :return: (CdnDecrypter, first chunk file data) N )keyZivr)r offsetlimit)r request_token)rZencryption_keyZ encryption_ivbytesr r rrrr isinstancerrrget_filer encryptpopcheck)r rZ cdn_redirectr decryptercdn_filecdn_hashrrrprepare_decrypter s2      zCdnDecrypter.prepare_decryptercCsZ|jrJ|jd}|t|j|j|j}|j|j |_ | |j |n t t d}|S)z Calls GetCdnFileRequest and decrypts its bytes. Also ensures that the file hasn't been tampered. :return: the CdnFile result. r) rrr rr rrr rrrr)rr"r!rrrrLs  zCdnDecrypter.get_filecCst||jkrtdS)z Checks the integrity of the given data. Raises CdnFileTamperedError if the integrity check fails. :param data: the data to be hashed. :param cdn_hash: the expected hash. N)rdigesthashr )datar"rrrr_s zCdnDecrypter.checkN) __name__ __module__ __qualname____doc__r staticmethodr#rrrrrrr s +r N)r*hashlibrZtl.functions.uploadrrZtl.types.uploadrrZcryptorerrorsr r rrrrs