Product Key

[Guest]

I want to produce a product key based upon the Product name, a purchase date
and one or two other fields, that is provided to the user to register their
database. I have code for encryting passwords but that produces a lot of
characters that are not keyable. I need to find an algorithm that restricts
the coded information to alphanumeric.

Does anyone have any examples of this.

 

[Ken Snell \(MVP\)]

Here are two functions that I often use as a "group" for these types of
purposes. Just list all the characters that are valid in the Select Case
part of the second function:



Public Function GetARandomCharacter() As String
Dim xlngAsciiNum As Long

On Error Resume Next

Randomize
Do
xlngAsciiNum = Int((256 * Rnd) + 1)
If IsAValidRandomCharacter(xlngAsciiNum) = True Then
GetARandomCharacter = Chr(xlngAsciiNum)
Exit Do
End If
Loop

Exit Function
End Function


Private Function IsAValidRandomCharacter(xlngAsciiNumber As Long) As Boolean
On Error Resume Next

Select Case xlngAsciiNumber

Case Asc("a") To Asc("z"), Asc("A") To Asc("Z"), _
Asc("0") To Asc("9")

IsAValidCharacter = True


Case Else
IsAValidCharacter = False

End Select
Exit Function
End Function

 

[Guest]

Thanks for you reply.

I have looked at the code below and I can't quite work out from the example
how I would use it to translate a string into a key. The same string has to
be translated into the same key each time, possibly with the use of a coding
string or number.

 

[Ken Snell \(MVP\)]

The functions won't do creation and translation of a specific key; you'd
need to write other programming to do that. I posted these functions in
response to my understanding that you were asking how to limit the randomly
chosen characters to a specific set of characters.

 

[Guest]

OK. You have missunderstood the problem. The characters are not random and
must produce the same result every time, otherwise you can never validate
them. The routines that I have can both produce an encrypted string, and
then decrypt that result to give the original input. While I don't
necessarily have to be able to decrypt this result, I will have to be able to
reproduce it to validate the user entered key.

 

[Ken Snell \(MVP\)]

Sorry, I am unable to help you with this issue. Perhaps another person can
give you some assistance.
--

Ken Snell
<MS ACCESS MVP>