Different Zip File Size for Excel with and without Workbook Protec

[DDoodle]

Hi all,

I have a problem when trying to distribute Excel file to several people. The
problem is with the Size.

The EXCEL file size is 7.90 MB.

Here's what happened:
1. When EXCEL is not password protected, Zip file size = 1.18Mb
2. When EXCEL is Sheet password protected for Sheet with or blank password,
the Zip file size = 1.18Mb
3. When EXCEL is Workbook password protected for Workbook with blank
password, the Zip file size = 1.18Mb

4. BUT ... When EXCEL is Workbook protected with Password, the Zip file size
= 7.24 Mb ????

Anybody know why the ZIP sizes are different?

p.s. It is necessary to protect the hidden sheets with workbook password
protected (so other normal people could not unhide), but with that size, it
is not wise to distribute through email.

Regards,
DDoodle

Excel - Excel2000 (9.0.4402.SR-1)

 

[NickHK]

It would seem that when you protect the workbook with a password, the actual
binary data is altered in the saved WB so the zip algorithm is not as
efficient at reducing file size. You can see this by looking at the files in
a Hex editor.
A quick test with XL2002, shows a reduction from 2362K > 312K without a
password, but only >2031K with a password.

I fail to see how you could get an increase in file size with a zip
operation; the worst situation would be no/very little change, as you
generally see with jpg file, as they are already highly compressed.

Maybe see what happens with one of the other compression algorithms; WinRar
etc.

NickHK