Introduction

SSL/TLS Certificates are used to secure HTTP connections between JOC Cockpit, Controller and Agents, for example JS7 - JOC Cockpit HTTPS Connections.

Users can choose one of the approachs specified with RFC5280:

  • Self-issued Certificates are created individually per user and are not applicable within reasonable effort for deploying individual certificate files to JS7 products.
  • Private CA-signed Certificates are issued by users who operate their own Private Certificate Authority (CA).
  • Public CA-signed Certificates are issued by a trusted Certificate Authority (CA) that validates the domain owner. They are not created by users but are purchased from the trusted CA and are not in scople of this article.

There is no difference in using a Private CA or Public CA concerning functionality of X.509 certificates, usage for Server Authentication / Client Authentication, or security of connections. The only difference is that users trust the Private CA that they set up on their own.

Examples in the article make use of JS7 Release 2.7.2, OpenSSL 1.1.1k  FIPS 25 Mar 2021 for Unix and OpenSSL 3.1.4 24 Oct 2023 for Windows. OpenSSL ships with Linux & other Unix OS and is available for Windows.

Setting up the Private CA

Creating the Private Key and Certificate Signing Request

Users have the option to use ECDSA or RSA for the encryption type applied to the Private Key.

Users can run the following commands from the shell and replace the value of the ca_key_name environment variable with a name of their choice that is used when creating related files.

Using ECDSA Encryption

Example how to create Private Key and Certificate Signing Request using ECDSA encryption (Unix)
# Specify key name used for file names
ca_key_name=root-ca

# Create Private Key
openssl ecparam -genkey -name secp384r1 -out ${ca_key_name}.key

# Create Certificate Signing Request
openssl req -new -sha512 -nodes \
    -key ${ca_key_name}.key \
    -out ${ca_key_name}.csr \
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${ca_key_name}"
Example how to create Private Key and Certificate Signing Request using ECDSA encryption (Windows)
@rem Specify key name used for file names
set ca_key_name=root-ca
 
@rem Create Private Key
openssl ecparam -genkey -name secp384r1 -out %ca_key_name%.key
 
@rem Create Certificate Signing Request 
openssl req -new -sha512 -nodes ^
    -key %ca_key_name%.key ^
    -out %ca_key_name%.csr ^
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%ca_key_name%"
  • Users should adjust the ca_key_name environment variable specifying a value that matches the purpose such as root-ca for a Root CA Certificate.
  • Private Key
    • Choice of algorithm such as secp256k1, secp384r1 depends on support by the Java version used with JS7.
  • Certificare Signing Request
    • The hash algorithm such as -sha256, -sha512 can be freely chosen.
    • The -subj option specifies the Distinguished Name used for the subject of the CSR and resulting Certificate.
      • The Distinguished Name is a unique identifier frequently using the hierarchy of Country C, State ST, Location L, Organization O, Organizational Unit OU and Common Name CN.
      • For the Private Root CA Certificate the subject and issuer properties of the CSR/Certificate are the same. The minimum requirement is to specify the Common Name CN=<name> where <name> can freely be chosen.
      • For Private CA-signed Certificates the subject property holds the Certificate's Distinguished Name and the issuer property holds the Private CA Certificate's Distinguished Name using different values.
  • The following files will be created with this step:
    • The root-ca.key file will hold the Private Key.
    • The root-ca.csr file will hold the Certificate Signing Request.

Using RSA Encryption

Example how to create Private Key and Certificate Signing Request using RSA encryption (Unix)
# Specify key name used for file names
ca_key_name=root-ca

# Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes \
    -keyout ${ca_key_name}.key \
    -out ${ca_key_name}.csr \
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${ca_key_name}"
Example how to create Private Key and Certificate Signing Request using RSA encryption (Windows)
@rem Specify key name used for file names
set ca_key_name=root-ca
 
@rem Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes ^
    -keyout %ca_key_name%.key ^
    -out %ca_key_name%.csr ^
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%ca_key_name%"
  • In the example the Private Key is created using the specified key size 4096.
  • For use of the -sha256 hash algorithm and -subj option see Using ECDSA Encryption.
  • The following files will be created with this step:
    • The root-ca.key file will hold the Private Key.
    • The root-ca.csr file will hold the Certificate Signing Request.

Creating the CA Certificate

Steps include to create the root-ca.crt Private CA-signed Certificate file in PEM format.

Users can run the following commands from the shell and replace the value of the ca_key_name environment variable with a name of their choice that is used when creating related files.

Example how to create CA Certificate (Unix)
# Specify key name used for file names
ca_key_name=root-ca

# Create Certificate
openssl x509 -req -sha512 -days 7305 \
    -signkey ${ca_key_name}.key \
    -in ${ca_key_name}.csr \
    -out ${ca_key_name}.crt \
    -extfile <(printf "basicConstraints=CA:TRUE\nkeyUsage=critical,nonRepudiation,keyCertSign,cRLSign\n")
Example how to create CA Certificate (Windows)
@rem Specify key name used for file names
set ca_key_name=root-ca
 
@rem Create Certificate
set ca_csr_tmp_file=ca-csr-%RANDOM%.tmp
copy /Y NUL %ca_csr_tmp_file%
echo basicConstraints=CA:TRUE >> %ca_csr_tmp_file%
echo keyUsage=critical,nonRepudiation,keyCertSign,cRLSign >> %ca_csr_tmp_file%

openssl x509 -req -sha512 -days 7305 ^
    -key %ca_key_name%.key ^
    -in %ca_key_name%.csr ^
    -out %ca_key_name%.crt ^
    -extfile %ca_csr_tmp_file%

del /q %ca_csr_tmp_file%
  • The SHA option such as -sha256, -sha384, -sha512 can be freely chosen.
  • The -days option specifies the validity period of the CA Certificate that should be longer than the validity period of individual certificates signed by the CA later on.
  • The -signkey option specifies the location of the Private Key file created from the previous step.
  • The -in option specifies the location of the Certificate Signing Request file created from the previous step.
  • The -out option specifies the location of the resulting Certificate file.
  • The -extfile option specifies the Basic Constraint CA:TRUE which is required for a CA Certificate. Key Usage is limited to signing certificates.
  • The following files will be created with this step:
    • The root-ca.crt file will hold the CA Certificate.

Creating SSL/TLS Server Certificates

For a given server next steps includes to create the Private Key and Certificate Signing Request (CSR). The resulting Server Certificate will be signed by the Private CA. 

This step is performed for each Server Certificate that should be created.

Users can run the following commands from the shell and replace the value of the server_name environment variable with a name of their choice that is used when creating related files.

Creating the Private Key and Certificate Signing Request

Using ECDSA Encryption

Example how to create Private Key and Certificate Signing Request using ECDSA encryption (Unix)
# Specify key name used for file names
server_name=myhost

# Create Private Key
openssl ecparam -genkey -name secp384r1 -out ${server_name}.key

# Create Certificate Signing Request
openssl req -new -sha512 -nodes \
    -key ${server_name}.key \
    -out ${server_name}.csr \
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${server_name}" 
Example how to create Private Key and Certificate Signing Request using ECDSA encryption (Windows)
@rem Specify key name used for file names
set server_name=myhost

@rem Create Private Key
openssl ecparam -genkey -name secp384r1 -out %server_name%.key

@rem Create Certificate Signing Request
openssl req -new -sha512 -nodes ^
    -key %server_name%.key ^
    -out %server_name%.csr ^
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%server_name%"

Using RSA Encryption

Example how to create Private Key and Certificate Signing Request using RSA encryption (Unix)
# Specify key name used for file names
server_name=myhost

# Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes \
    -keyout ${server_name}.key \
    -out ${server_name}.csr \
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${server_name}"
Example how to create Private Key and Certificate Signing Request using RSA encryption (Windows)
@rem Specify key name used for file names
set server_name=myhost

@rem Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes ^
    -keyout %server_name%.key ^
    -out %server_name%.csr ^
    -subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%server_name%"

Creating the Server Certificate

Example how to create and sign Server Certificate (Unix)
# Specify server for which the certificate should be created
server_name=myhost

# Create and sign Server Certificate
openssl x509 -req -sha512 -days 3652 \
    -in ${server_name}.csr \
    -CA root-ca.crt \
    -CAkey root-ca.key \
    -CAcreateserial \
    -out ${server_name}.crt \
    -extfile <(printf 'subjectAltName=DNS:%s\nkeyUsage=critical,keyEncipherment,digitalSignature\nextendedKeyUsage=serverAuth,clientAuth\n' "${server_name}")
Example how to create and sign Server Certificate (Windows)
@rem Specify key name used for file names
set server_name=myhost

@rem Create and sign Server Certificate
set server_crt_tmp_file=server-crt-%RANDOM%.tmp
copy /Y NUL %server_crt_tmp_file%
echo subjectAltName=DNS:%server_name% >> %server_crt_tmp_file%
echo keyUsage=critical,keyEncipherment,digitalSignature >> %server_crt_tmp_file%
echo extendedKeyUsage=serverAuth,clientAuth >> %server_crt_tmp_file%
 
openssl x509 -req -sha512 -days 3652 ^
    -in %server_name%.csr ^
    -CA root-ca.crt ^
    -CAkey root-ca.key ^
    -CAcreateserial ^
    -out %server_name%.crt ^
    -extfile %server_crt_tmp_file%

del /q %server_crt_tmp_file%
  • The following files will be created for the given server:
    • myhost.crt: the Server Certificate
  • For operation with JS7 JOC Cockpit, Controller and Agents users can add

Resources

Shell Scripts

As an alternative to running OpenSSL commands in an interactive shell, scripts are provided that perform this task.

The below scripts assume the following directory layout:

  • <ca>  The directory <ca> is a placeholder. Any directory can be used.
    • create_root_ca.sh
    • create_server_certificate.sh
    • certs
    • csr
    • private

The sub-directories certs, csr and private will be created should they not exist.

Creating the Private Root CA Certificate

Download: create_root_ca.sh

The following files will be created when executing the script:

  • <ca>/certs/root-ca.crt
  • <ca>/csr/root-ca.csr
  • <ca>/private/root-ca.key

This step is performed just once. In case of renewal of the Root CA Certificate any Server Certificates will have to be renewed.

Run create_root_ca.sh shell script
# Description
# create_root_ca.sh --key-name=<basename> --subject=<distinguished-name> --days=<number-of-days>

# Example for use with defaults
./create_root_ca.sh

# Example for use with basename
./create_root_ca.sh --key-name=ca-root

# Example applying specific distinguished name and lifetime
./create_root_ca.sh --subject="/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=JS7 CA" --days=7660


The shell script is optionally executed with the following arguments:

  • --key-name
    • The basename of the key without extension. Default: root-ca
  • --subject
    • The distinguished name that is used as the subject of the CA Certificate. Default: /C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=Root CA
  • --days
    • The lifetime of the certificate is specified by the number of days. Default: 7305
    • Consider that Server Certificates have to be renewed if the Root CA Certificate expires.

Creating a Server Certificate

Download: create_server_certificate.sh

The following files will be created with <server> being a placeholder for the hostname for which a certificate should be created.

  • <ca>/certs/<server>.crt
  • <ca>/csr/<server>.csr
  • <ca>/private/<server>.key

This step is performed for each Server Certificate that should be created.

Run create_server_certificate.sh shell script
# Description
# create_server_certificate.sh --dns=<hostname>[,<hostname>] --key-name=<basename> --subject=<distinguished-name> --days=<number-of-days>

# Example for use with DNS and lifetime
./create_server_certificate.sh --dns=centostest-primary --days=365

# Example for use with DNS, key name and lifetime
./create_server_certificate.sh --dns=centostest-primary,centostest-primary.sos --key-name=centostest-primary --days=4017

# Example for use with DNS, subject and lifetime
./create_server_certificate.sh --dns=centostest-primary,centostest-primary.sos --subject="/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=centostest-primary.sos" --days=4017 


The shell script is executed with the following arguments:

  • --dns (required)
    • The DNS hostname of the server that should be assigned the certificate. A server can be assigned more than one DNS hostname, for example the FQDN can extend the hostname. Only DNS hostnames that are added to the certificate can be used later on to establish secure HTTPS connections.
  • --key-name
    • The basename of the key without extension. Default: root-ca
  • --subject
    • The distinguished name that is used as the subject of the Server Certificate. Default: /C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=<dns>
    • The CN attribute must specify the server's hostname. By default the first hostname specified with the --dns option is used.
  • --days
    • The lifetime of the certificate is specified by the number of days. Default: 3652