# openssl
openssl genrsa -out private.pem 2048
openssl rsa -in private.pem -pubout -out public.pem

# ssh-keygen
ssh-keygen -t rsa -P "" -b 4096 -m PEM -f jwtRS256.key
ssh-keygen -e -m PEM -f jwtRS256.key > jwtRS256.key.pub