decryption question

David Shaw dshaw at
Thu Apr 18 05:31:42 CEST 2013

On Apr 17, 2013, at 5:06 PM, "Beith, Linda" <lbeith at> wrote:

> Hi folks,
> Please excuse cross-posting but I wasn’t sure which list was the best option for my dilemma. 
> I am new to the list and am hoping someone can provide some suggestions for a situation we have at my University. We have had a rather catastrophic loss of all data from one of our Fall 2012 courses on our Sakai open source learning management server. To compound matters, we have a military student who had an incomplete in that course and is on deadline to finish his work and submit his grades or face being dropped from his academic program. 
> Since our Sakai instance is hosted by a third-party vendor we don’t have direct access to the application at the server level, so each month the vendor makes a backup copy of our full database and encrypts/zips it using GNU PG so we can download it.  We then decrypt it using the passcode they provide and we can run stats against the resulting SQL file.
> I had a backup file from early December 2012 that I had downloaded but never opened. I sent the file back to our vendor in hopes of being able to retrieve the course data however when they  tried to unzip/decrypt it, they were not prompted for the passcode and just got an error:
> Gpg: can’t open ‘rwu.dbdump_Nov2012.sql.gz.gpg’
> Gpg: decrypt_message filed: file open error
> We can’t have them redo the backup because it is too late – the files are no longer on their server. So the only source of the work is locked in this zipped file. The zipped file is quite large – over 1 GB so we know there is data there – we just can’t get to it.
> The assumption is  that something went wrong in the original encryption of the file. Do you have idea if it is possible to extract data in this situation? 
> I appreciate any help or suggestions you can provide,

A few questions:

If it doesn't work to decrypt it at the vendor, does it work if you decrypt it locally like you normally do when you run stats against the SQL?

What version of GPG is your vendor using (run "gpg --version" to check) ?

What platform is your vendor running GPG on (Linux / Other Unix-like / Windows / etc.) ?

How do you download the file from your vendor once they create it (i.e. ftp, http, scp ... ?)  How did you send it back to them for decryption?

That specific error message indicates that the decryption hadn't even started yet.  For example, it's the error you would get if you ran "gpg --decrypt this-file-does-not-exist.gpg".


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