I would like to generate a certificate(self-signed at the moment) for an encrypted PDF on the server. What is interesting to me is the workflow on how to to that with TCPDF.
I hope you also took a look at the comments ;) there is a mini how to setup the pdf using provided file
especially:
// To open the document you need to install the private key (tcpdf.p12) on the Acrobat Reader. The password is: 1234
however, you need to provide setProtection with existing key:
'c' => 'file://../tcpdf.crt'
the path you given is just showing where you need to give the path, but the path itself need to be changed
Summary: please read again the comments in the example 016 file, they WILL help to get it working the way you need