[VB.NET] RC4 Encryption Module

Code:
Public Shared Function rc4(ByVal message As String, ByVal password As String) As String



        Dim i As Integer = 0

        Dim j As Integer = 0

        Dim cipher As New StringBuilder

        Dim returnCipher As String = String.Empty



        Dim sbox As Integer() = New Integer(256) {}

        Dim key As Integer() = New Integer(256) {}



        Dim intLength As Integer = password.Length



        Dim a As Integer = 0

        While a <= 255



            Dim ctmp As Char = (password.Substring((a Mod intLength), 1).ToCharArray()(0))



            key(a) = Microsoft.VisualBasic.Strings.Asc(ctmp)

            sbox(a) = a

            System.Math.Max(System.Threading.Interlocked.Increment(a), a - 1)

        End While



        Dim x As Integer = 0



        Dim b As Integer = 0

        While b <= 255

            x = (x + sbox(b) + key(b)) Mod 256

            Dim tempSwap As Integer = sbox(b)

            sbox(b) = sbox(x)

            sbox(x) = tempSwap

            System.Math.Max(System.Threading.Interlocked.Increment(b), b - 1)

        End While



        a = 1



        While a <= message.Length



            Dim itmp As Integer = 0



            i = (i + 1) Mod 256

            j = (j + sbox(i)) Mod 256

            itmp = sbox(i)

            sbox(i) = sbox(j)

            sbox(j) = itmp



            Dim k As Integer = sbox((sbox(i) + sbox(j)) Mod 256)



            Dim ctmp As Char = message.Substring(a - 1, 1).ToCharArray()(0)



            itmp = Asc(ctmp)



            Dim cipherby As Integer = itmp Xor k



            cipher.Append(Chr(cipherby))

            System.Math.Max(System.Threading.Interlocked.Increment(a), a - 1)

        End While



        returnCipher = cipher.ToString

        cipher.Length = 0



        Return returnCipher



    End Function