Create a CA certificate and issue client certificates with it.

issue-cert.sh

#!/bin/bash

# Parameters
# ====================================================================================

# Color Alias
NO_COLOR='\033[0m'
RED_BG='\033[7;49;31m'
RED='\033[1;49;31m'
GREEN_BG='\033[7;49;32m'
GREEN='\033[1;49;32m'
ORANGE_BG='\033[7;49;33m'
ORANGE='\033[1;49;33m'
BLUE_BG='\033[7;49;34m'
BLUE='\033[1;49;34m'
PURPLE_BG='\033[7;49;35m'
PURPLE='\033[1;49;35m'
CYAN_BG='\033[7;49;36m'
CYAN='\033[1;49;36m'
WHITE_BG='\033[7;49;37m'
WHITE='\033[1;49;37m'
LIGHT_ORANGE_BG='\033[7;49;93m'
LIGHT_ORANGE='\033[1;49;93m'

# Functions
# ====================================================================================

function welcome {
  echo -e "${GREEN}Welcome to Certificate Issuer${NO_COLOR}"
}

function issue_ca {
  echo -e "${WHITE}Let's issue new CA certificate.${NO_COLOR}"
  read -p "Common Name (CN) : " cname
  read -p "Organization (O) : " org
  openssl req -x509 -newkey rsa:4096 -keyout $1/ca_key.pem -out $1/ca_cert.pem -nodes -days 365 -subj "/CN=${cname}/O=${org}"
  echo -e "${WHITE}CA certificate saved to $1.${NO_COLOR}"
}

function issue_client {
  echo -e "${WHITE}Let's issue new client certificate.${NO_COLOR}"
  read -p "Common Name (CN) : " cname
  openssl req -newkey rsa:4096 -keyout $1/${cname}_key.pem -out $1/${cname}_csr.pem -nodes -days 365 -subj "/CN=${cname}"
  openssl x509 -req -in $1/${cname}_csr.pem -CA $1/ca_cert.pem -CAkey $1/ca_key.pem -out $1/${cname}_cert.pem -set_serial 01 -days 365
  openssl pkcs12 -export -clcerts -in $1/${cname}_cert.pem -inkey $1/${cname}_key.pem -out $1/${cname}.p12
  echo -e "${WHITE}Client certificate saved to $1.${NO_COLOR}"
}

function view_ca {
  openssl x509 -in $1/ca_cert.pem -noout -text
}

function view_client {
	local cert_dir=$1
	read -p "Enter the client's Common Name (CN) : " cname
	local cert_file=$1/${cname}_cert.pem
	if [ -f ${cert_file} ]; then
		openssl x509 -in ${cert_file} -noout -text
	else
		echo -e "${RED}Client not found.${NO_COLOR}"
	fi
}

# Main
# ====================================================================================

welcome

read -p "Select a certificate directory : " cert_dir
if [ ! -d "${cert_dir}" ]; then
    mkdir -p ${cert_dir}
fi
if [ -f "${cert_dir}/ca_key.pem" ] && [ -f "${cert_dir}/ca_cert.pem" ]; then
  echo -e "${WHITE}CA certificate found.${NO_COLOR}"
  read -p "View CA (0) or issue client (1) or view client (2) ? " opt
  if [ "${opt}" == 0 ]; then
    view_ca ${cert_dir}
  elif [ "${opt}" == 1 ]; then
    issue_client ${cert_dir}
	elif [ "${opt}" == 2 ]; then
		view_client ${cert_dir}
  else
    echo -e "${RED}Unknown option.${NO_COLOR}"
  fi
else
  echo -e "${WHITE}No CA certificate found.${NO_COLOR}"
  issue_ca ${cert_dir}
fi