self-renewal password in Excel

[trillicomm]

I have two concerns. Excel's password feature can be disabled once you know the password. Second, if not diabled, it is the same password at all times. Well, I want to create a self-renewal password for opening an excel file. For every 15th days of the every month, the password changes itself. For ex: the original password is "temp11". If the file is open AFTER the 15th day of month April, it creates the next password such as "temp23". The format of the password is similar: always "temp" plus "increment of 1" plus "ascending prime numbers". However, it must have a permanent master password to disable the self-renewal password. My client knows the self-renewal password but not the master one. Any advise?

Best regards,
T. Le
This message was edited by trillicomm on 2002-03-19 16:06
This message was edited by trillicomm on 2002-03-19 16:13

 

[LMF]

I don't think is possible to do this with the Excel protection...

u need to do it with a dialog box and coding... that should do.

good luck

 

[trillicomm]

I totally agree with you. How to code that is what I am interested.

 

[Jack in the UK]

No reason why you can have password chage to pre defind PW on > 1st jan or > 15 jan or > 1 feb etc

but your need to know the new password, odd that, so you need to memorise many passwords, or be sneeky.

If this is sheet protection add cqll in autoopen so password jumps.

if module.. not so easy.. .

remember passwords can be opened cracked, regardless..

take some VBA to do this thou....

 

[trillicomm]

The file has 27 sheets and I don't have any module. I am still clueless.

 

[Jack in the UK]

Module is where the code is places,

Auto_open calls the reqd code, or can really be in auto_open i guess..

 

[trillicomm]

I am sorry...I am still clueless. I am not a VBA expert. I need more step by step advise. Thank you.

 

[Chris Davison]

Trillicom,

that prime number bit may be a bit of a drag..... unless you have a pretty big database of existing prime numbers, you're going to have to have excel figure out the next one...

since a prime number is not divisible by anything except itself and "1", you need to check that it's not divisible by all the integers between 3 and it's own square root. Asking excel to do this may take some time and thusly affect it's performance...even via VBA, as each new password requires this whole checking procedure up to the next prime number....

 

[Jack in the UK]

Thus my comments, no reason why password 1 cant change to password 2 in 15 days, bit still a crude idea...