Having a commandline-cryptography tool that supports more options than mcrypt would be handy here. I found no easy-to-use implementation of that. From what I read in Schneier (✺pplied cryptography«), there is an ecb variant using ciphertex stealing that avoids padding. This decrypts the first 256 bytes correctly, after that it seems to mix up things (the correct decryption continues at byte 512). Mcrypt -d -a blowfish-compat -s 16 -o hex -b -noiv -m ecb -nodelete -f The best I got till now was using mcrypt with ecb-mode: The encrypted and decrypted files are exactly the same size, that means we have no IV and a variant of blowfish that does no padding. This already gives us the possibility to manually download the key and, if we want to re-decode some movie (because we lost the wmv or because we want to decode a file before it's completely downloaded to already start watching the recording), save the key to a local webserver as uncrypt.php, forward the hostname to 127.0.0.1 and re-start otrdecoder.įrom what I found out yet, the file is encrypted with some sort of blowfish. Inside that file is an ascii/hex-encoded number with 128 bit. Using some network sniffer, the authentication is very simple, it just requests them with http, the URL is otrkey-format, which can be decoded using their binary otrdecoder-tool, considering you have requested the recording in advance.Īs there is no information how the format and authentication work, I had a deeper look at it. Onlinetvrecorder, a service that let's you record broadcasts from some german television stations, provides it's files in.
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