[Solved] Calc file encryption algorithm?

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[Solved] Calc file encryption algorithm?

Postby fifagenis » Fri Sep 08, 2017 4:31 am

I am new to Calc and password protected a calc file. Unfortunately, I couldn't remember it clearly. What kind of encryption algorithm does calc use? Is it possible to brute-force the password like zip file, which I did it successfully on Windows.
Last edited by fifagenis on Fri Sep 15, 2017 9:16 am, edited 1 time in total.
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Re: Calc file encryption algorithm?

Postby MrProgrammer » Fri Sep 08, 2017 5:26 am

Hi, and welcome to the forum.

fifagenis wrote:I am new to Calc and password protected a calc file. Unfortunately, I couldn't remember it clearly.
My advice about passwords is in section 6. Saving your data and making backups of Ten concepts that every Calc user should know.

You can also read Password Recovery.

fifagenis wrote: Is it possible to brute-force the password like zip file, which I did it successfully on Windows.
I would assume that will not be easy. I have read that OpenOffice uses "strong encryption". What is the point in providing password protection if it is simple to circumvent? However if one has used a weak password, say just the letter "x", any encryption algorithm is vulnerable.

If this solved your problem please go to your first post use the Edit button and add [Solved] to the start of the title. You can select the green checkmark icon at the same time.
Last edited by MrProgrammer on Fri Sep 08, 2017 6:08 pm, edited 1 time in total.
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Re: Calc file encryption algorithm?

Postby John_Ha » Fri Sep 08, 2017 10:12 am

fifagenis wrote:Is it possible to brute-force the password like zip file, which I did it successfully on Windows.

AOO files are zip files so rename the file to a zip file and try it.
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Re: Calc file encryption algorithm?

Postby fifagenis » Sat Sep 09, 2017 4:18 am

MrProgrammer wrote:Hi, and welcome to the forum.

fifagenis wrote:I am new to Calc and password protected a calc file. Unfortunately, I couldn't remember it clearly.
My advice about passwords is in section 6. Saving your data and making backups of Ten concepts that every Calc user should know.

You can also read Password Recovery.

fifagenis wrote: Is it possible to brute-force the password like zip file, which I did it successfully on Windows.
I would assume that will not be easy. I have read that OpenOffice uses "strong encryption". What is the point in providing password protection if it is simple to circumvent? However if one has used a weak password, say just the letter "x", any encryption algorithm is vulnerable.


Thanks. I learn my lesson so I will write the password and backup file in future.

John_Ha wrote:
fifagenis wrote:Is it possible to brute-force the password like zip file, which I did it successfully on Windows.

AOO files are zip files so rename the file to a zip file and try it.


Thanks for sharing this trick. I will test it out.
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Re: Calc file encryption algorithm?

Postby robleyd » Sat Sep 09, 2017 5:24 am

For those interested, here is the AOO Wiki page discussing encryption.
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Re: Calc file encryption algorithm?

Postby fifagenis » Thu Sep 14, 2017 11:19 am

MrProgrammer wrote:Hi, and welcome to the forum.

fifagenis wrote:I am new to Calc and password protected a calc file. Unfortunately, I couldn't remember it clearly.
My advice about passwords is in section 6. Saving your data and making backups of Ten concepts that every Calc user should know.

You can also read zip Password Unlocker.

fifagenis wrote: Is it possible to brute-force the password like zip file, which I did it successfully on Windows.
I would assume that will not be easy. I have read that OpenOffice uses "strong encryption". What is the point in providing password protection if it is simple to circumvent? However if one has used a weak password, say just the letter "x", any encryption algorithm is vulnerable.

If this solved your problem please go to your first post use the Edit button and add [Solved] to the start of the title. You can select the green checkmark icon at the same time.


there are many password recovery tools out there, most of them used brute-force to crack password like zip, rar or doc. you can google it.
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