How to encrypt a column in MS Access?

You can use the AfterUpdate event to encrypt, and the got focus event to decrypt. There's tons of code on the net, but here's a simple one that works. Just put it in a standard module:

The following function will work to both encrypt and decrypt a string:

Note :

Mid Function : Returns a Variant (String) containing a specified number of characters from a string.

Syntax : Mid(string, start[, length])

Mod Operator : Used to divide two numbers and return only the remainder.

Syntax : result = number1 Mod number2

Asc Function : Returns an Integer representing the character code corresponding to the first letter in a string.

Syntax : Asc(string)

Xor Operator : Used to perform a logical exclusion on two expressions.

Syntax : [result =] expression1 Xor expression2

Public Function Encrypt(ByVal strIn As String, ByVal strCode As String) As String

On Error GoTo Error_Handler

Dim i As Integer

Dim bytData As Byte

Dim bytKey As Byte

Dim strEncrypted As String

Encrypt = vbNullString

For i = 1 To Len(strIn)

bytData = Asc(Mid(strIn, i, 1))

bytKey = Asc(Mid(strCode, (i Mod Len(strCode)) + 1))

strEncrypted = strEncrypted & Chr(bytData Xor bytKey)

Next i

If strEncrypted <> vbNullString Then

Encrypt = strEncrypted

End If

Exit_Here:

Exit Function

Error_Handler:

Resume Exit_Here

End Function