加密代码

Private Function JiaMi(ByVal No As String) As String
        Dim Key, Pass As String
        Dim i, code, j As Integer
        Dim HashCryptoService As HashAlgorithm
        HashCryptoService = New SHA256Managed
        Dim bytIn As Byte() = UTF8Encoding.UTF8.GetBytes(No)
        Dim bytOut As Byte() = HashCryptoService.ComputeHash(bytIn)
        Key = Convert.ToBase64String(bytOut)
        If Key.Length > 12 Then
            Key = Key.Substring(0, 8)
        End If
        Key = Key.ToUpper()
        For i = 0 To 7
            code = AscW(Key.Substring(i, 1))
            If code < 48 Then
                j = code Mod 10
                j = j + 48
                Pass += ChrW(j)
            ElseIf code < 57 Then
                Pass += ChrW(code)
            ElseIf code < 65 Then
                j = code Mod 10
                j = j + 65
                Pass += ChrW(j)
            ElseIf code < 90 Then
                Pass += ChrW(code)
            Else
                j = code Mod 10
                j = 90 - j
                Pass += ChrW(j)
            End If
        Next
        MsgBox(Pass, MsgBoxStyle.Information, "")
        Return Pass
    End Function