Generate Random Password for PDF with asp.net

In the previous article we discussed about Dynamic PDF generation with static password.Now Lets try with some random password that means generate a password at the time of pdf creation to provide more secuirty for the pdf file.


Previous article :


Create Password protected PDF using iTextsharp

First ,Drag one label from toolbox and change properties as

Name =" "(Empty)

Id=lblPassword

Visible=false;

Now, write a method to generate a random password with the combination of string and number

private string setpassword()
{
    StringBuilder SB = new StringBuilder();
    SB.Append(RandomString(3, true));
    SB.Append(RandomNumber(100, 999));    
    return SB.ToString();
}

The following method return a random number

private int RandomNumber(int min, int max)
{
Random random = new Random();
return random.Next(min, max); 
}

The following method return a random string

StringBuilder SB = new StringBuilder();
    Random random = new Random();
    char ch ;
    for(int i=0; i lessthan size; i++)
    {
        ch = Convert.ToChar(Convert.ToInt32(Math.Floor(26 * random.NextDouble() + 65))) ;
        SB.Append(ch); 
    }
    if(lowerCase)
    return SB.ToString().ToLower();
    return SB.ToString();

Now write the following method to generate a PDF file

First get the generated password in to label,Write the following code inside the button event

protected void btnCreatePDF_Click(object sender, EventArgs e)
    {
    
        lblPassword.Text=setpassword();
        
    }
   

Following is the complete code to generate pdf file with random password

protected void btnCreatePDF_Click(object sender, EventArgs e)
    {
    
        lblPassword.Text=setpassword();
        
        string path = Server.MapPath("~/");
        string fileName =txtPDFName.Text + ".pdf";
        string MFileName = string.Empty;
        object TargetFile = path + fileName;
       
        iTextSharp.text.pdf.PdfReader reader = new iTextSharp.text.pdf.PdfReader(TargetFile.ToString());
        MFileName = TargetFile.ToString();
        MFileName = MFileName.Insert(ModifiedFileName.Length - 4, "R2T4");
        
        lblpassword.Text=Setpassword();
        
        iTextSharp.text.pdf.PdfEncryptor.Encrypt(reader, new FileStream(MFileName, FileMode.Append), iTextSharp.text.pdf.PdfWriter.STRENGTH128BITS, lblpassword.Text, "", iTextSharp.text.pdf.PdfWriter.AllowPrinting);
        if (File.Exists(TargetFile.ToString()))
            File.Delete(TargetFile.ToString());         
        
    }

Previous article :

Create Password protected PDF using iTextsharp

I Hope this will helps somebody..Happy Coding....