password with special chars not working

[czarly]

i can encrypt pdfs using special chars in the password, but i cannot open them in the pdf viewer. it reports an incorrect password.

i tried to encode the pdf with the qpdf command line tool and found a passage in the manual saying:

In all cases where qpdf allows specification of a password, care
must be taken if the password contains characters that fall
outside of the 7-bit US-ASCII character range to ensure that the
exact correct byte sequence is provided.  It is possible that a
future version of qpdf may handle this more gracefully.  For
example, if a password was encrypted using a password that was
encoded in ISO-8859-1 and your terminal is configured to use
UTF-8, the password you supply may not work properly.

They suggest further down to use iconv to convert charsets but I didn't get there yet. also i want to use node-qpdf not the command line utility.