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This
seminar has several goals. You will:
1.
Learn how to scramble data in your tables to hide
sensitive information
2.
Convert text characters to their ASCII equivalent values
and back
3.
Perform mathematical obfuscation on your data
4.
Control access to the form that handles the encryption / decryption
We will begin by building a simple
customer table that will hold all of our information. The public
information (name, address, etc.) that doesn't need to be encrypted will
just have a single field. The private data (credit limit, notes, etc.)
will have an extra field for the encrypted value.
We'll set up a public customer form - again with just the data
that everyone can see (in this case, just the customer's name). We'll
make a button to open a private form that has the secret data. Now, I
show you how to control WHO can gain access to these records inside the
database in my
Security Seminar. In that Seminar you learn how to set up user
and group accounts, and control who can see what forms, reports, and
data.
Then we'll build a second form to show the private data. There
will be VBA code that runs when the form opens that decrypts
(unscrambles) any hidden data (in this case, the credit limit and
notes). Then when the user clicks the "Save & Close" button, those
fields are encrypted again and the data saved to the table. I'll show
you how to lock this form down so the user MUST click on your
Save button to close it, which runs your code.
Now if anyone happens to come across your back-end database file that
contains your tables, all they will see is gibberish in the table
itself. The actual data has been wiped, and they see garbage.
This solution isn't perfect. Someone can still erase or edit your data.
That's one of the problems with Microsoft Access... the back-end tables
aren't secure. This solution, however, will allow you the best possible
means for keeping people from viewing sensitive data in your database
without having an actual database server. Of
course, if you have any questions about whether or not this seminar is
for you, please contact me.
Access Data Encryption Seminar - Outline
00. Intro (5:02)
01. Lesson 1 (9:06)
Set up the database
Set up customer table with encryption fields
Create customer form for public data
Create customer form for encrypted data
02. Lesson 2 (9:37)
Button to open encrypted form
Encrypt Function
Creating a public function in a module
ASCII values & table
ASC() Function
For Next Loop
Mid() Function
03. Lesson 3 (9:41)
Convert Integers to String Values
CStr() Function
Len() Function
Const Keyword to create Constants
Key Values to Mathematically Obfuscate Data
04. Lesson 4 (9:40)
Convert String Values to Integers
CInt Function
Converting ASCII Values to Characters
CHR() Function
Convert to Currency Values
CCur() Function
MsgBox Command
Global Constants
05. Lesson 5 (7:59)
Decrypt Function
Reversing the Encryption Procedure
For Next Step
Deleting actual data from the table
06. Lesson 6 (7:58)
Save & Close Button
&& to get one &
DoCmd.Close Command
Decrypt the data when the form loads
OnCurrent Event
Hide the Encrypted Fields
Visible Property
Control how users can close the form
Only allow closing form with your button
Form Properties
Navigation Buttons
Record Selectors
Scrollbars
Control Box
Close Button
Max Min Buttons
Pop Up
Modal
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