[HaBo]

private void Button1_Click(object sender, EventArgs e)
{
    int num;
    long num2;
    string s = "";
    string str3 = "";
    bool flag = true;
    if (Strings.Len(this.TextBox1.Text) == 5)
    {
        int num3 = this.TextBox1.TextLength - 1;
        for (num = 1; num <= num3; num++)
        {
            num2 = Conversions.ToLong(Conversions.ToString(num2) + Conversions.ToString(Strings.Asc(this.TextBox1.Text[num])));
        }
    }
    if (Strings.Len(num2.ToString()) >= 10)
    {
        num2 = Conversions.ToLong(Strings.Mid(Conversions.ToString(num2), 2, 8));
    }
    string str = this.wert(num2);
    int num4 = str.Length - 1;
    for (num = 0; num <= num4; num += 5)
    {
        string zahl = Strings.Mid(str, num + 1, 5);
        string str5 = Conversions.ToString(this.Quersumme(zahl));
        s = s + str5;
    }
    str3 = this.TextBox4.Text + this.TextBox5.Text + this.TextBox6.Text + this.TextBox7.Text;
    byte[] bytes = Encoding.ASCII.GetBytes(s);
    byte[] buffer = Encoding.ASCII.GetBytes(str3);
    MD5CryptoServiceProvider provider = new MD5CryptoServiceProvider();
    byte[] buffer3 = provider.ComputeHash(bytes);
    byte[] buffer4 = provider.ComputeHash(buffer);
    int num5 = buffer3.Length - 1;
    for (num = 0; num <= num5; num++)
    {
        if (buffer4[num] == buffer3[num])
        {
            flag = false;
        }
        else
        {
            flag = true;
            break;
        }
    }
    if (!flag)
    {
        this.TextBox3.Text = "PASS";
    }
    else
    {
        this.TextBox3.Text = "FAIL";
    }
}

Private Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim num As Integer
    Dim num2 As Long
    Dim s As String = ""
    Dim str3 As String = ""
    Dim flag As Boolean = True
    If (Strings.Len(Me.TextBox1.Text) = 5) Then
        Dim num3 As Integer = (Me.TextBox1.TextLength - 1)
        num = 1
        Do While (num <= num3)
            num2 = Conversions.ToLong((Conversions.ToString(num2) & Conversions.ToString(Strings.Asc(Me.TextBox1.Text.Chars(num)))))
            num += 1
        Loop
    End If
    If (Strings.Len(num2.ToString) >= 10) Then
        num2 = Conversions.ToLong(Strings.Mid(Conversions.ToString(num2), 2, 8))
    End If
    Dim str As String = Me.wert(num2)
    Dim num4 As Integer = (str.Length - 1)
    num = 0
    Do While (num <= num4)
        Dim zahl As String = Strings.Mid(str, (num + 1), 5)
        Dim str5 As String = Conversions.ToString(Me.Quersumme(zahl))
        s = (s & str5)
        num = (num + 5)
    Loop
    str3 = (Me.TextBox4.Text & Me.TextBox5.Text & Me.TextBox6.Text & Me.TextBox7.Text)
    Dim bytes As Byte() = Encoding.ASCII.GetBytes(s)
    Dim buffer As Byte() = Encoding.ASCII.GetBytes(str3)
    Dim provider As New MD5CryptoServiceProvider
    Dim buffer3 As Byte() = provider.ComputeHash(bytes)
    Dim buffer4 As Byte() = provider.ComputeHash(buffer)
    Dim num5 As Integer = (buffer3.Length - 1)
    num = 0
    Do While (num <= num5)
        If (buffer4(num) = buffer3(num)) Then
            flag = False
        Else
            flag = True
            Exit Do
        End If
        num += 1
    Loop
    If Not flag Then
        Me.TextBox3.Text = "PASS"
    Else
        Me.TextBox3.Text = "FAIL"
    End If
End Sub