/** Sets the encryption options for this document. The userPassword and the
* ownerPassword can be null or have zero length. In this case the ownerPassword
* is replaced by a random string. The open permissions for the document can be
* AllowPrinting, AllowModifyContents, AllowCopy, AllowModifyAnnotations,
* AllowFillIn, AllowScreenReaders, AllowAssembly and AllowDegradedPrinting.
* The permissions can be combined by ORing them.
* @param userPassword the user password. Can be null or empty
* @param ownerPassword the owner password. Can be null or empty
* @param permissions the user permissions
* @param strength128Bits <code>true</code> for 128 bit key length, <code>false</code> for 40 bit key length
* @throws DocumentException if anything was already written to the output
*/
public void SetEncryption(byte[] userPassword, byte[] ownerPassword, int permissions, bool strength128Bits)
{
if (stamper.append)
{
throw new DocumentException("Append mode does not support changing the encryption status.");
}
if (stamper.ContentWritten)
{
throw new DocumentException("Content was already written to the output.");
}
stamper.SetEncryption(userPassword, ownerPassword, permissions, strength128Bits);
}
