About aes decrypt

[boygiandi]

Hi.
I'm trying to convert an PHP video crawler script to youtube-dl (python). Link was encrypted by AES, I'm using this library in PHP to decrypt https://github.com/ivantcholakov/gibberish-aes-php .
It's very simple to use :

$media_url = GibberishAES::dec("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", 'phimbathu.com45904818776707');

Result

https://redirector.googlevideo.com/videoplayback?id=c497980b7f982b0b&itag=18&source=webdrive&requiressl=yes&ttl=transient&mm=30&mn=sn-i3b7kn7y&ms=nxu&mv=u&pl=48&ei=hczJWPSYOcvoqQX81quACg&mime=video/mp4&lmt=1487699254560815&mt=1489619994&ip=2001:ee0:305:1::16&ipbits=0&expire=1489634502&sparams=ip,ipbits,expire,id,itag,source,requiressl,ttl,mm,mn,ms,mv,pl,ei,mime,lmt&signature=5F649791D284F0816D2E0C088CC32E3D85435CD5.417A9FA3CAD7FB623AEA310F08A72699C7DFD74C&key=ck2&app=explorer

But when I use aes_decrypt_text in youtube-dl with the same params, it show error

print aes_decrypt_text("U2FsdGVkX1/v3lNRMc7N7chKwkk89sjJr5xu4SLxC8DzV+DN9aZEelQ0jJcOcYg+I4KDLfgPPKAk28LpSmsqMFGYjPfn0684hKx+gfk4r9uyLoiiXs2eEsPaSEy06p+BV1QNQJuoykIpDZkeV0zWXKaqZhkz4iwHGTsMzxAFkIEvsd4JVe1JVapnTklCYRfLOt7tlkFTqfKxCpIaQFqe7hz0eLW3rPcfEk6ASBE7ue8/ETe/ziEAlH3k1D6zt6c7lb1wNtWMTIIuFGkrKV5WanKQwezMQ0ywsBe76jOR1DkynU62pJU/CUMtcprYhz0HzNHy8JKyji22uUIyskmZ6Ehk2tNJtStA0Yyq4B/u9e/PmGYJsfUEDW5M3XSQIGGHCS89o/LtELl4TlzdhcfsZbCl6BR+q8zOE+hYt9fRfhSuJOVT8bv1rN2AaQRydZBrGtBENUR12MzwERQasg9po/6WhVJyiKb+2cuOebJlkXt11bw20wsFTRgnTNlL6he9McHwtvDwRgspHHVmcTIv/Q4h2g8khfY2L5NmFf0smgdQoMey1sDezuoowNIrRnJKN5ysJ/Np3B+G+9HCLVJDwBwt91wm89/CWOSsTP0iuT7bDerL8ezWdLehiCJfD6r/9EJwlyPqtARewNLth56k1y3UFuOu/le9BAMTixiEIWU=", 'phimbathu.com45904818776707', 32).decode('utf-8')

File "/usr/lib64/python2.7/encodings/utf_8.py", line 16, in decode return codecs.utf_8_decode(input, errors, True) UnicodeDecodeError: 'utf8' codec can't decode byte 0xad in position 1: invalid start byte

Please help me.

[yan12125]

From aes.py:

Mode of operation is 'counter'

youtube-dl's aes_decrypt_text uses CTR mode, and gibberish-aes-php uses CBC. You can call aes_cbc_decrypt instead.

[boygiandi]

aes_cbc_decrypt(data, key, iv)

In this case, can you show me what is iv ?

aes_cbc_decrypt("....base 64string....", "phimbathu.com45904818776707", iv)

Thanks

[yan12125]

Gibberish's function uses a custom IV value: https://github.com/ivantcholakov/gibberish-aes-php/blob/master/GibberishAES.php#L164

By the way, aes_cbc_decrypt uses int lists, so you need intlist_to_bytes and bytes_to_intlist.