Excel password not working

S

shaking

Registered User
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I was sent an e-mail with a password protected spreadsheet, the password was also sent to me but it's not working! The person who mailed me is uncontactable for the next few hours and I need to open it urgently anyone know a way round?
 
A quick google suggests that there is lots of "Excel Crack" software out there which claims it will do the job, but having never used any I'd be very slow to suggest one.

Also some claims that copying > relocating > renaming > playing with the properties of the file can give a workaround, but I'd be very surprised if this technique did work (what's the point in security if it isn't secure).
 
you can save it as a .txt file - and open it to see the contents - you will have to read through a lot of formatting junk - but you will be able to see whats in it that way.
 
shaking said:
Thanks for the tips I looked at it as a txt file
Click to expand...
Slightly scary that a "protected" file can be viewed so easily.

Is there any way to secure a document/file in a manner which requires a serious effort (obviously, most security can be bypassed with the correct equipment/knowledge... but being able to view as a .txt is a little too easy) to bypass? (I know you can password protect PDF files and zipped files, are these just as easy to bypass?)
 
it just so happens that excel format is very easy to read if you do that.

most files that are microsoft standard (.doc, .xls...) are easy to do that to - you can use a hexidecimal editor if there is a lot of junk in it - makes it easier (if you can read hexadecimal).

I would imagine .pdf if much less easy to open - as its saved like an image.
 
What you need is software to encrypt (code) your documents and the recipient(s) need the same software to decrypt (decode) the documents when they receive them.

To do this you need to -

1) Generate two keys - one for yourself and the other for the recipient -
2) Send one key to recipient
3) Encrypt document using your key
4) Transmit encrypted document
5) Recipient decrypts document using the key you sent them
6) At random intervals generate and distribute new keys

There's tons of stuff available as shareware, freeware, commercial desktop software that use both public and private key encryption which a quick search will find for you, depending on you operating system.

Satanta said:
...(I know you can password protect PDF files and zipped files, are these just as easy to bypass?)
Click to expand...
Yes
 
Just to correct a few misconceptions :-

1. Thanks for the tips I looked at it as a txt file

Password protected excel files can't be viewed in plain text. The whole file would be gobbledegook. If you did view it, then it wasn't password protected. Btw, excel allows two levels of password protection one to prevent writing to the file, the other to prevent reading. Its the latter I'm referring to.

2. it just so happens that excel format is very easy to read if you do that

Well its not that easy, and quite difficult if there are numbers in the spreadsheet - they're stored in binary and are not human readable.

3. Is there any way to secure a document/file in a manner which requires a serious effort

Yes. But it'll be a bit more time consuming for you. As poster above describes public key systems are the business for this. But it's actually fairly easy to operate - a good freeware package for this is gpg.

But weigh up your options here. Password protection by the likes of excel/winzip/adobe are breakable, but only by manually unscrambling the key. This is quite difficult to do and most widely available hacks for this are based on firing dictionary entries at it in the hope of matching the password. So if your password isn't that obvious ie. isn't a word or a date of birth etc. then it would take a fair amount of work to break in - well beyond scriptkiddies. imo, this kind of protection is adequate. If you're careful/paranoid, use gpg.
 

1 above - it will display as gobbledegook but you can eyeball the gobbledegook to get to the info you are interested in, password protected or not.

2 above - untrue - the numbers are perfectly readable as usually people have them stored as text columns - this would not be a practical solution to viewing a large spreadsheet full of information, but it can work in a pinch.

The OPs experience speaks for itself, couldnt open a password protected excel file, viewed it as a .txt, got the info they needed.
 

OK, I'm just wondering if we're talking about the same thing here. Excel 97/2000 gives you two password options - to open and to modify. I'm talking about the "to open" option which completely scrambles the contents with 40bit rc4 encryption.

Just to test this, I created two files. The first one has approx 101 lines and is saved with a "open" password. The 2nd is saved as normal but has 2 columns of number data.

When I view these files with a text editor - notepad etc, no data is visible. In the encrypted file, as expected apart from the header and trailer (contains file property data), the data part looks like randomised ascii. In the numbers file, the numbers are stored in what looks like 4 or 8 byte float format. Don't have the actual excel spec to hand but both of these results are entirely as expected. I could email you the files if you pm me your address! Try it yourself and let us know the results.
 
interesting - i just tried it - you are quite correct about the 'open' password protected file. So I am now surprised it worked for the OP - unless the password was the 'modify' one? (dont know if it works for that)

on the other type (no password protect) - i had viewed a file that had both numbers and text in columns (ie 'ABC123'), plain numeric does not work - but in my own experience, i dont get many spreadsheets with plain numbers in them - theres a currency symbol or a a character as above etc...
 
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