Decrypt AES-encoded HLS streams

dec_hls.py

#!/usr/bin/env python3

from __future__ import print_function
import argparse
from Crypto.Cipher import AES


READ_AT_ONCE = 1 << 16

ap = argparse.ArgumentParser()
ap.add_argument('-k', '--keyfile', required=True, help='use key file')
ap.add_argument('-o', '--output', required=True, help='set output')
ap.add_argument('-c', '--cipher', help='set cipher type')
ap.add_argument('FILES', help='files to decode', nargs='+')
args = ap.parse_args()

with open(args.keyfile, 'rb') as keyfile:
    secret_key = keyfile.read()

IV = "\0" * 16

aes = AES.new(secret_key, AES.MODE_CBC, IV)

with open(args.output, 'wb') as outfile:
    print('OUTFILE: {}'.format(args.output))
    for filename in args.FILES:
        with open(filename, 'rb') as infile:
            print('INFILE: {} '.format(filename), end='')
            while True:
                inbuf = infile.read(READ_AT_ONCE)
                outbuf = aes.decrypt(inbuf)
                outfile.write(outbuf)
                print('.', end='')

                if len(inbuf) < READ_AT_ONCE:
                    break
            print()

usage.txt

$ cat files
segment1_2000000_av.ts
segment2_2000000_av.ts
segment3_2000000_av.ts
segment4_2000000_av.ts
segment5_2000000_av.ts
segment6_2000000_av.ts
segment7_2000000_av.ts
segment8_2000000_av.ts
segment9_2000000_av.ts
segment10_2000000_av.ts

$ cat files | xargs ./dec_hls.py -k crypt.key -o output.ts
OUTFILE: output.ts
INFILE: segment1_2000000_av.ts ............................................
INFILE: segment2_2000000_av.ts ............................................
INFILE: segment3_2000000_av.ts ...........................................
INFILE: segment4_2000000_av.ts ......................................
INFILE: segment5_2000000_av.ts ..........................................
INFILE: segment6_2000000_av.ts ...............................
INFILE: segment7_2000000_av.ts ....................................................
INFILE: segment8_2000000_av.ts .......................................
INFILE: segment9_2000000_av.ts ......................................
INFILE: segment10_2000000_av.ts .

$ ffmpeg -y -i output.ts -c:v copy -c:a copy -movflags +faststart -bsf:a aac_adtstoasc output.m4v