![]() ![]() dat files for us) has passed on to the otherworld where obsolete hardware goes once it malfunctions. More specifics of the system shouldn't be necessary, but the reason this issue has occurred is because our front-end system that shared the symmetric key (and auto-appended the. If the current file that it wants to decrypt/decompress, matching the #_#.dat signature, isn't encrypted then it bails too. ![]() Note that simply adding unencrypted files won't suffice - the system uses a hardware token for the encryption/decryption key (which is why I can't possibly recover it) AND it tries to decrypt each file individually using the logic: 1) lists archive 2) sorts by the above names where the first 2 digits represent the month 01-12 and the second 2 digits represent the year for 1997-2014 3) and then tries to extract the NEWEST file first - bail upon first decryption failure. to a backup file that the backend system can read. Since these tools recover key's 0-2 (3x 4-byte key triplet) per the zip 2.0 appnote (scroll to nearly the very end), in theory would it then be possible for those tools (or a modified open source zip utility that can write encrypted zip 2.0 archives) to initialize the keyset with the known-to-decrypt key triplet, generate a 12-byte 'random', and then use these values to add additional files to the existing archive? However, I am not interested in recovering the contents. There are various tools out there that can 'break' the zip 2.0 encryption with a known-plaintext attack, which allows recovery of the contents. However, I need to be able to add new files to existing encrypted archives. I don't have the ability to determine/recover the master password for a production system that uses zip 2 archives.
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