Problems with Digital Signature

[brownti via OfficeKB.com]

I am having some trouble with a macro filled template that i created. I have
a workbook that has many different macros in it so i first digitally signed
it and then saved it as an excel template. I then distributed it to a couple
of co-workers to use on their computers. When opening for the first time i
installed the signature like i thought i was supposed to and enabled macros
and always trust the source. After the template was opened on their computer
they saved it as a different name and .xls file. Then while working on it,
it attempted to autosave and they got an error message saying they did not
have the correct signature for the modified project and the signature would
be discarded. Any ideas why this is happening or did i do something
incorrectly? After signing the code i did make some revisions without
resigning, just saving. Could that have something to do with it? I have
searched high and low and cant find necessary information to help. I
appreciate any help you can give.

 

[Shailesh Shah]

Regards,
Shah Shailesh
http://in.geocities.com/shahshaileshs/
(Excel Add-ins Page)

 

[Shailesh Shah]

After every revisions, you need to sign again.

Regards,
Shah Shailesh
http://in.geocities.com/shahshaileshs/
(Excel Add-ins Page)

 

[brownti via OfficeKB.com]

I need to resign after all revisions to macros, not the workbook though,
correct?

 

[Guest]

This is only an opinion but the digital signature does not seem practical for
VBA projects since they can be modified so easily by people other than the
authors. I think the idea for the digital signatures was more for the type
code that can be compiled and secured from the general public for
modification.

 

[Guest]

"After signing the code i did make some revisions without
resigning, just saving."

This breaks the signing. You sign the code in state X and a checksum is
calculated behind the scenes. Change the code and the checksum is
recalculated and it will not match - hence a problem

Digital signatures are quite fragile - you have to get a robust prcess in
plae to ensure you sign the right thing.

 

[brownti via OfficeKB.com]

The reason for signing was so that users dont have to choose to enable macros
everytime they use the workbook. I am not aware of any other way. The users
will not be changing the code, just the worksheets, so the signature should
work fine correct?

"After signing the code i did make some revisions without
resigning, just saving."

This breaks the signing. You sign the code in state X and a checksum is
calculated behind the scenes. Change the code and the checksum is
recalculated and it will not match - hence a problem

Digital signatures are quite fragile - you have to get a robust prcess in
plae to ensure you sign the right thing.

I am having some trouble with a macro filled template that i created. I have
a workbook that has many different macros in it so i first digitally signed

[quoted text clipped - 10 lines]

searched high and low and cant find necessary information to help. I
appreciate any help you can give.