iTextSharp not protecting PDF with password

Question

I am using iTextSharp 5 and trying to password protect already existing PDF file but it is not working. When I double click on new password protected file then Microsoft Edge simply opens without asking for password. Here is my code:

public void PasswordProtectPDF(string source, string destionation, string pass)
{
      using (Stream input = new FileStream(source, FileMode.Open, FileAccess.Read, FileShare.Read))
      {
            using (Stream output = new FileStream(destionation, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                  PdfReader reader = new PdfReader(input);
                  PdfReader.unethicalreading = true;
                  PdfEncryptor.Encrypt(reader, output, true, null, pass, PdfWriter.ALLOW_SCREENREADERS);
            }
      }
}

What am I doing wrong?

EDIT

I tried iText8 but same issue. Able to open PDF without password. Here is my code:

public void PasswordProtectPDF(string source, string destionation, string pass)
{
      using (Stream input = new FileStream(source, FileMode.Open, FileAccess.Read, FileShare.Read))
      {
            using (Stream output = new FileStream(destionation, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                PdfReader reader = new PdfReader(input);
                reader.SetUnethicalReading(true);
                EncryptionProperties encryptionProperties = new EncryptionProperties();
                encryptionProperties.SetStandardEncryption(null, Encoding.ASCII.GetBytes(pass), EncryptionConstants.ALLOW_PRINTING, EncryptionConstants.STANDARD_ENCRYPTION_128);
                PdfEncryptor.Encrypt(reader, output, encryptionProperties);
            }
      }
 }

EDIT

Fixed the issue. Just need to change one line as below:

encryptionProperties.SetStandardEncryption(Encoding.ASCII.GetBytes(pass), null, EncryptionConstants.ALLOW_PRINTING, EncryptionConstants.STANDARD_ENCRYPTION_128);

Answer 1

Here is correct code for iText 8

public void PasswordProtectPDF(string source, string destionation, string pass)
{
      using (Stream input = new FileStream(source, FileMode.Open, FileAccess.Read, FileShare.Read))
      {
            using (Stream output = new FileStream(destionation, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                PdfReader reader = new PdfReader(input);
                reader.SetUnethicalReading(true);
                EncryptionProperties encryptionProperties = new EncryptionProperties();
                encryptionProperties.SetStandardEncryption(Encoding.ASCII.GetBytes(pass), null, EncryptionConstants.ALLOW_PRINTING, EncryptionConstants.STANDARD_ENCRYPTION_128);
                PdfEncryptor.Encrypt(reader, output, encryptionProperties);
            }
      }
 }