Create your server's self signed SSL Certificates on Ubuntu16.04LTS

root@dlp:~# 

cd /etc/ssl/private 

root@dlp:/etc/ssl/private# 

openssl genrsa -aes128 -out server.key 2048 

Generating RSA private key, 2048 bit long modulus
.......+++
......................................................................+++
e is 65537 (0x10001)
Enter pass phrase for server.key:     # set passphrase
Verifying - Enter pass phrase for server.key:     # confirm

# remove passphrase from private key

root@dlp:/etc/ssl/private# 

openssl rsa -in server.key -out server.key 

Enter pass phrase for server.key:     

# passphrase

writing RSA key
root@dlp:/etc/ssl/private# 

openssl req -new -days 3650 -key server.key -out server.csr 

You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:

JP

     

# country

State or Province Name (full name) [Some-State]:

Hiroshima

     

# state

Locality Name (eg, city) []:

Hiroshima

     

# city

Organization Name (eg, company) [Internet Widgits Pty Ltd]:

GTS

     

# company

Organizational Unit Name (eg, section) []:

Server World

     

# department

Common Name (e.g. server FQDN or YOUR name) []:

dlp.srv.world

     

# server's FQDN

Email Address []:

xxx@srv.world

    

# email address

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:

An optional company name []:

root@dlp:/etc/ssl/private# 

openssl x509 -in server.csr -out server.crt -req -signkey server.key -days 3650 

Signature ok
subject=/C=JP/ST=Hiroshima/L=Hiroshima/O=GTS/OU=Server World/CN=dlp.srv.world/emailAddress=xxx@srv.world
Getting Private key
root@dlp:/etc/ssl/private# 

chmod 400 server.*

ที่มา : https://www.server-world.info/en/note?os=Ubuntu_16.04&p=ssl