Home Forums .NET libraries Xceed Zip & Real-Time Zip for .NET Recover a file from a truncated Zip archive

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    #20387 |

    I’ve got a Zip archive that has been truncated so that the central directory is gone and the last file remaining within the archive is only a partial entry.  I’m able to get all the intact files from the archive using the ZipReader, but not the last partial entry at the tail end that was truncated.  Any thoughts on how I might go about decrypting/uncompressing and extracting the data that is there in what remains of that last file entry?

    Thanks,

    -Steve 

    Imported from legacy forums. Posted by Steve (had 1799 views)

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    I’ve got the block of data from the archive entry in question, but it is encrypted (I know the key) and compressed. Since it uses AES-256 it seems that I should be able to use the same algorithm to decrypt the data.  I will also need to decompress.  A couple of questions come to mind:

    1. when being added to an archive is data first compressed and then encrypted, or vice versa?  I believe I would need to reverse the order to decrypt and uncompress.

    2. what compression algorithm is used by default?

     

    Thanks,

    -Steve 

    Imported from legacy forums. Posted by Steve (had 312 views)

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    For anyone interested, as it turns out, the ZipReader stream will extract out the data up to the point of truncation.

    Imported from legacy forums. Posted by Steve (had 623 views)

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    [quote user=”Steve”]

    I’ve got a Zip archive that has been truncated so that the central directory is gone and the last file remaining within the archive is only a partial entry.  I’m able to get all the intact files from the archive using the ZipReader, but not the last partial entry at the tail end that was truncated.  Any thoughts on how I might go about decrypting/uncompressing and extracting the data that is there in what remains of that last file entry?

    Thanks,

    -Steve 

    [/quote]

    [url=http://www.recoverytoolbox.com/repair_zip.html]zip repair[/url] crashed by viruses and other malware, which may intentionally corrupt zip archives, incorrect operation of anti-viral software and other software and hardware issues. Tool repair encrypted data from ZIP archives, SFX files. It restores ZIP files from damaged media (floppy disks, CDs, DVDs, Zip drives, etc.).

    Imported from legacy forums. Posted by John (had 1201 views)

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