Create Self-signed Certificate

Without Root CA

openssl req -new -newkey rsa:2048 -days 365 -nodes -x509 -keyout server.key -out server.crt

With Root CA

1. Create a root CA.

   # generate the private key
   openssl genrsa -out ca.key 2048 -nodes
   # generate the certificate
   openssl req -new -x509 -key ca.key -out ca.crt -days 3650

   -days: number of days the certificate will be valid for.

2. Create a server private key and Certificate Signing Request (CSR).

   # generate the private key
   openssl genrsa -out server.key 2048
   # generate the CSR to be signed
   openssl req -new -key server.key -out server.csr

3. Sign the CSR by the root CA.

   openssl x509 -req -days 365 -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out server.crt

   -days: number of days the certificate will be valid for.