Comment on Ask HN: Decode Youtube 500 pageparentComments−aeon10OP12yActually the first few characters remained the same with page loads.−nwh12yCBC mode AES?−drdaeman12yMore likely a header. It's 3081 byte blob after base64 decoding. If we consider it's encrypted with some block cipher with 128 or 256-bit blocks (IV and/or MAC would be likely to be 128-bit, too), there are 9 bytes for some header and/or padding.−nwh12yGood catch.
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Actually the first few characters remained the same with page loads.
CBC mode AES?
More likely a header. It's 3081 byte blob after base64 decoding. If we consider it's encrypted with some block cipher with 128 or 256-bit blocks (IV and/or MAC would be likely to be 128-bit, too), there are 9 bytes for some header and/or padding.
Good catch.