cert = /etc/stunnel/stunnel.pem
CAfile = /etc/stunnel/stunnel.crt

openssl req -new -sha256 -key /etc/stunnel/stunnel.key -out /etc/stunnel/stunnel.csr

ciphers = PSK
PSKsecrets = /etc/stunnel/psk.txt

PSKsecrets = /etc/stunnel/psk-client1.txt

client1:Wf44zFw33FeMxCqobcA13lb28IgizxyZJOUoUsZGlkk