Comment 24 for bug 404647

cmc->dr/hbrinkm/kohei: Attached is an implementation of the MS XML decryption
mechanism. I've only done the decryption work and hard-coded the password to the
classic Excel default "VelvetSweatshop", which means that applied and
out-of-the-box it's able to open "protected" documents like
http://download.microsoft.com/download/7/E/7/7E7662CF-CBEA-470B-A97E-CE7CE0D98DC2/ISA_PNPID_List.xlsx

but someone needs to extend it to query/accept used-entered passwords, and/or
break it up, move it around, check for failures at the various intermediate
steps return values

openssl is in the "vanilla" build-tree, so I've implemented it using that, so it
should be ok from that sense.

FWIW, one quirk of their "bundle it into a OLE2 package and encrypt the whole
zip as a stream in that package" mechanism is that it won't be possible to
detect the file type until *after* its bee decrypted