The Password used for PDF encryption in the line - [m_doc encryptAs:docPath :@"user" :@"admin" :0x4 :4 :&c];
i.e. User Password - "user" , Owner Password - "admin" is not working for opening the encrypted PDFs.
Request you to kindly provide us with the Password for the same, if it is not the one as specified above.
can you share the slice of code used to encrypt the file?
If the Premium license is correctly activated and the encryption method returns true, you should be able to open the encrypted file with the chosen passwords.
Encryption is AES128bit.
We support also 256bit (level8) but you should pay attention: PDF1.7 standard officially support only the 128bit version as the 256 was affected by a weakness in the key handling.
PDF1.8level8 introduced again the 256bit version but may PDF viewer doesn't support it as it introduces a different way to encrypt streams.