//**************************************
    //     
    // Name: RegCodes
    // Description:This class contains two f
    //     unctions which can be helpful in creatin
    //     g an online shareware registration syste
    //     m for your software projects. GenerateKe
    //     yCode takes a username, or any other str
    //     ing, and generates a unique human-readab
    //     le registration code (such as 9397-JQM0L
    //     D0YJV from the string: Andy Carrasco). G
    //     enerateKeyCode will generate a totally u
    //     nique registration code over and over ag
    //     ain, even for the exact same name! Verif
    //     yKeyCode is the partner function, and wi
    //     ll verify if a keycode matches a given n
    //     ame.
    // By: Andy Carrasco
    //
    // Side Effects:IMPORTANT NOTE!
    Although the codes generated from this algorithm will throughly confuse, and secure your code from, the average user, I make absolutely no gaurantee of security. The average hacker is NOT the average user, and anyone with a fairly general understanding of cyphering could quickly crack these algorithms. On the other hand, there are NO registration code utilities which gaurantee security, it would be foolish to believe that any form of encryption is totally secure. You may freely, and are encouraged to, use this algorithm in your own registration utilities, provided that you fully understand that I do not gaurantee the security of these functions, and that I will take no liability for any losses occuring from your use of these functions. They are primarily intended as a learning facility. 
    Andy Carrasco
    //
    //This code is copyrighted and has    // limited warranties.Please see http://
    //     www.Planet-Source-Code.com/xq/ASP/txtCod
    //     eId.1199/lngWId.-10/qx/vb/scripts/ShowCo
    //     de.htm    //for details.    //**************************************
    //     
    
    Option Explicit
    ' Name: GenerateKeyCode
    '
    ' Description:
    'This little routine generates a keycode for shareware registration in the
    'format XXXX-YYYYYYYYYY, based on the Name given as an argument. The first
    'four digits are a randomly generated seed value, which makes 8999 possible keycodes
    'for people with the same name (like John Smith). The last four digits are
    'the actual code.
    '
    ' Written by:
    'Andy Carrasco (Copyright 1998)
    '
    Public Function GenerateKeyCode(sName As String) As String
    Dim sRandomSeed As String
    Dim sKeyCode As String
    Dim X As Long
    Dim KeyCounter As Long
    Dim PrimaryLetter As Long
    Dim CodedLetter As Long
    Dim sBuffer As String
    Randomize
    sRandomSeed = CStr(Int((9999 - 1000 + 1) * Rnd + 1000))
    sName = UCase$(sName)
    KeyCounter = 1
    'Clean up sName so there are no illegal characters.
    For X = 1 To Len(sName)
    If Asc(Mid$(sName, X, 1)) >= 65 And Asc(Mid$(sName, X, 1)) <= 90 Then sBuffer = sBuffer & Mid$(sName, X, 1)
    Next X
    sName = sBuffer
    'if the name is less than 10 characters long, pad it out with ASCII 65
    Do While Len(sName) < 10
    sName = sName + Chr$(65)
    Loop
    For X = 1 To Len(sName)
    PrimaryLetter = Asc(Mid$(sName, X, 1))
    CodedLetter = PrimaryLetter + CInt(Mid$(sRandomSeed, KeyCounter, 1))
    If CodedLetter < 90 Then
    sKeyCode = sKeyCode + Chr$(CodedLetter)
    Else
    sKeyCode = sKeyCode + "0"
    End If
    'Increment the keycounter
    KeyCounter = KeyCounter + 1
    If KeyCounter > 4 Then KeyCounter = 1
    Next X
    GenerateKeyCode = sRandomSeed + "-" + Left$(sKeyCode, 10)
    End Function
    ' Name: VerifyKeyCode
    '
    ' Description:
    'Verifies if a given keycode is valid for a given name.
    '
    ' Parameters:
    'sName- A string containing the user name to validate the key against
    'sKeyCode- A string containins the keycode in the form XXXX-YYYYYYYYYY.
    '
    Public Function VerifyKeyCode(sName As String, sKeyCode As String) As Boolean
    Dim sRandomSeed As String
    Dim X As Long
    Dim KeyCounter As Long
    Dim PrimaryLetter As Long
    Dim DecodedKey As String
    Dim AntiCodedLetter As Long
    Dim sBuffer As String
    sRandomSeed = Left$(sKeyCode, InStr(sKeyCode, "-") - 1)
    sName = UCase$(sName)
    sKeyCode = Right$(sKeyCode, 10)
    KeyCounter = 1
    'Clean up sName so there are no illegal characters.
    For X = 1 To Len(sName)
    If Asc(Mid$(sName, X, 1)) >= 65 And Asc(Mid$(sName, X, 1)) <= 90 Then sBuffer = sBuffer & Mid$(sName, X, 1)
    Next X
    sName = sBuffer
    'if the name is less than 10 characters long, pad it out with ASCII 65
    Do While Len(sName) < 10
    sName = sName + Chr$(65)
    Loop
    'now, decode the keycode
    For X = 1 To Len(sKeyCode)
    PrimaryLetter = Asc(Mid$(sKeyCode, X, 1))
    AntiCodedLetter = PrimaryLetter - CInt(Mid$(sRandomSeed, KeyCounter, 1))
    If PrimaryLetter = 48 Then 'zero
    DecodedKey = DecodedKey + Mid$(sName, X, 1) 'Take the corresponding letter from the name
    Else
    DecodedKey = DecodedKey + Chr$(AntiCodedLetter)
    End If
    'Increment the keycounter
    KeyCounter = KeyCounter + 1
    If KeyCounter > 4 Then KeyCounter = 1
    Next X
    If DecodedKey = Left$(sName, 10) Then
    VerifyKeyCode = True
    Else
    VerifyKeyCode = False
    End If
    End Function