Commonly Confused Letters for Numbers

A few .Net (VB) functions I recently created to use in a project.

The following is a simple random number generator with a few sub functions broken out to generate a random number and random true or false. I created a utility class which I will continue to build to meet new projects and from previous asp.net functions.

The following are what I consider the most commonly confused letters for numbers.

B = 8 (eight)
I = 1 (one)
L = 1 (one)
O = 0 (zero
S = 5 (five)
Z = 2 (two)

So basically the purpose of knowing this is to remove those letters and numbers from a username or password generator.

I googled for more information on this topic and couldn't find anything and I don't consider what I have as definitive, it's just what I could figure out.

I'm sure there is a better (more efficient) way to do most if not all of the functions below. If you have a suggestion feel free to post it in the comments.

Public Class Utility

    Public Shared Function SanitizeSQL(ByVal Input As String) As String

        'Strip Quotes

        Input = Input.Replace("'", "''")

        'Remove Harmful Chars

        Input = Input.Replace("SELECT", "").Replace("drop", "").Replace(";", "").Replace("--", "").Replace("insert", "").Replace("delete", "").Replace("xp_", "").Replace("|", "")

        Return Input

    End Function

    Public Shared Function MySQL_Date_Now() As String

        Return Format(Date.Now, "yyyy-MM-dd hh:mm:ss tt")

    End Function

    Public Shared Function MySQL_Date_Convert(ByVal Input As String) As DateTime

        Return Format(Date.Parse(Input), "yyyy-MM-dd hh:mm:ss tt")

    End Function

    Public Enum PasswordType As Integer

        LowerLettersOnly = 1

        UpperLettersOnly = 2

        NumbersOnly = 3

        NumbersAndLowerLetters = 4

        NumbersAndUpperLetters = 5

        NumbersAndMixedCaseLetters = 6

    End Enum

    Public Shared Function Random_Password( _

         Optional ByVal Length As Integer = 8 _

        , Optional ByVal Type As PasswordType = 1 _

        , Optional ByVal AddChars As String = "" _

        , Optional ByVal RemoveChars As String = "" _

        ) As String

        Dim Numbers_Bag = "34679" 'change to include more numbers

        Dim Letters_Bag = "acdefghjkmnpqrtuwvxy" 'change to include more letters

        Dim CharBag As String = ""

        If Type >= PasswordType.NumbersOnly Then

            CharBag = Numbers_Bag

        End If

        If Type <> PasswordType.NumbersOnly Then

            CharBag += Letters_Bag

        End If

        CharBag += AddChars

        For counter As Integer = 0 To RemoveChars.Length - 1

            If CharBag.IndexOf(RemoveChars.Substring(counter, 1)) >= 0 Then

                CharBag = CharBag.Remove(CharBag.IndexOf(RemoveChars.Substring(counter, 1)), 1)

            End If

        Next counter

        'Begin Creating Random Password

        Dim temp_string As New System.Text.StringBuilder

        For t As Byte = 1 To Length

            Dim random_char As Integer

            Randomize()

            random_char = Rnd() * (Len(CharBag) - 1)

            If Type = PasswordType.NumbersAndMixedCaseLetters And Random_True() = True Then

                temp_string.Append(CharBag.ToUpper.Trim.Chars(random_char))

            Else

                temp_string.Append(CharBag.Trim.Chars(random_char))

            End If

        Next

        Select Case Type

            Case PasswordType.NumbersAndUpperLetters, PasswordType.UpperLettersOnly

                Return temp_string.ToString.ToUpper

            Case Else

                Return temp_string.ToString

        End Select

    End Function

    Public Shared Function Random_True() As Boolean

        Return Random_Number(0, 1)

    End Function

    Public Shared Function Random_Number( _

          Optional ByVal LowerLimit As Integer = 0 _

        , Optional ByVal UpperLimit As Integer = 100000 _

        ) As Integer

        Randomize()

        Return CInt(Int(((UpperLimit - LowerLimit + 1) * Rnd()) + Int(LowerLimit)))

        'from MSDN Help - randomvalue = CInt(Int((upperbound - lowerbound + 1) * Rnd() + lowerbound))

    End Function

End Class