[VB] Random Str

'**************************************
' Name: Generate a random string, with a
' length within a range.
' Description:This code will take a rang
' e (lower and upper), and output a string
' of random characters (0-9, A-Z, a-z). I
' use this to generate a key for encryptio
' n, during the key negotiation phase of a
' connection to an encrypted server.
Usage is simple:
Dim sKey as String
sKey = GenerateKey(10,100)
' this code generates a key with a lengt
' h between
' 10 and 100 characters.
' By: Gregg Housh
'
' Inputs:iLower: Lowest possible length


' for the string
iUpper: Maximum length For the String
'
' Returns:Returns a string.
'
'This code is copyrighted and has' limited warranties.Please see http://w
' ww.Planet-Source-Code.com/xq/ASP/txtCode
' Id.21395/lngWId.1/qx/vb/scripts/ShowCode
' .htm'for details.'**************************************

' Credit goes to these people for code I
'
' borrowed/modified:
' Kevin Lawrence - non-repeating random
'
' number generator
' VBPJ - GenerateRandomNumberInRange
' (modified by me, from a shuffle routin
' e in VBPJ)


Public Function GenerateKey(ByVal iLower As Integer, ByVal iUpper As Integer) As String
Dim sKey As String
Dim sChar As String
Dim iLen As Integer
Dim iLoop As Integer
' dont need keys TOO big ...
iLen = GetRandomNumberInRange(iLower, iUpper)


For iLoop = 1 To iLen
' dont include quotes
Retry:


Do
sChar = Chr(GetRandomNumber())
Loop While sChar = Chr(34)
' make sure its 0-9, A-Z, or a-z


If Not IsValidChar(sChar) Then
Goto Retry:
Else
sKey = sKey & sChar
End If
Next iLoop
GenerateKey = sKey
End Function


Private Function IsValidChar(ByVal sChar As String) As Boolean
Dim btoggle As Boolean


If Asc(sChar) >= 48 And Asc(sChar) <= 57 Then
'valid #
btoggle = True
ElseIf Asc(sChar) >= 65 And Asc(sChar) <= 90 Then
'valid uppercase character
btoggle = True
ElseIf Asc(sChar) >= 97 And Asc(sChar) <= 122 Then
btoggle = True
Else
btoggle = False
End If
IsValidChar = btoggle
End Function


Public Function GetRandomNumberInRange(Lower As Integer, Upper As Integer) As Integer
Static PrimeFactor(10) As Integer
Static a As Integer
Static c As Integer
Static b As Integer
Static s As Long
Static n As Integer
Static n1 As Integer
Dim i As Integer
Dim j As Integer
Dim K As Integer
Dim m As Integer
Dim t As Boolean


If (n <> Upper - Lower + 1) Then
n = Upper - Lower + 1
i = 0
n1 = n
K = 2


Do While K <= n1


If (n1 Mod K = 0) Then


If (i = 0 Or PrimeFactor(i) <> K) Then
i = i + 1
PrimeFactor(i) = K
End If
n1 = n1 / K
Else
K = K + 1
End If
Loop
b = 1


For j = 1 To i
b = b * PrimeFactor(j)
Next j
If n Mod 4 = 0 Then b = b * 2
a = b + 1
c = Int(n * 0.66)
t = True


Do While t
t = False


For j = 1 To i
If ((c Mod PrimeFactor(j) = 0) Or (c Mod a = 0)) Then t = True
Next j
If t Then c = c - 1
Loop
Randomize
s = Rnd(n)
End If
s = (a * s + c) Mod n
GetRandomNumberInRange = s + Lower
End Function


Public Function GetRandomNumber() As Integer
Dim a(122) ' Sets the maximum number To pick
Dim b(122) ' Will be the list of new numbers (same as DIM above)
Dim ChosenNumber As Integer
Dim MaxNumber As Integer
Dim seq As Integer
'Set the original array
MaxNumber = 122 ' Must equal the Dim above


For seq = 0 To MaxNumber
a(seq) = seq
Next seq
'Main Loop (mix em all up)
Randomize (Timer)


For seq = MaxNumber To 0 Step -1
ChosenNumber = Int(seq * Rnd)
b(MaxNumber - seq) = a(ChosenNumber)
a(ChosenNumber) = a(seq)
Next seq
' return a random number from a random p
' osition in B()
GetRandomNumber = b(GetRandomNumberInRange(1, 122))
End Function