sudo apt-get update
sudo apt-get install libsrtp2-dev
./oprint/bin/pip3 install cryptography
Then enter your Raspberry Pi account and password to finish the installation.
Attention: If you get a prompt showing that the rust is missing during the installation process, please enter the command “sudo curl https://sh.rustup.rs -sSf | sh”, and then enter “1” according to the instruction.