Introduction
JS7 - Deployment of Scheduling Objects makes use of Signing Certificates to digitally sign workflows and other objects. Certificates are deployed to Controllers and Agents. Use of certificates for signing is not related to use of certificates to secure HTTPS connections, see JS7 - How to create X.509 SSL TLS Certificates.
Users can choose one of the approachs specified with RFC5280:
- Self-issued Certificates are created individually per user and are deployed from individual certificate files to Controllers and Agents.
- There is no security gap in use of self-issued Certificates. When users store certificate files to Controllers and Agents then this proves that they trust the certificates.
- Private CA-signed Certificates are issued by users who operate their own Private Certificate Authority (CA). Individual Signing Certficates on behalf of users are not deployed to Controllers and Agents. Instead, the CA Certificate is deployed that was used to sign individual Signing Certificates.
- The approach includes that any Signing Certificate signed by the CA will be accepted for deployment of scheduling objects.
- For better control which certificates are made available for deplyoment, users might decide to use a specific Private CA.
- Public CA-signed Certificates are issued by a trusted Certificate Authority (CA) that validates the domain owner. Such certificates are not created by users but are purchased from the trusted CA and are not in scope of this article.
There is no difference in using a Private CA or Public CA concerning functionality of X.509 certificates, usage for Signing, or security of certificates. The only difference is that users trust the Private CA that they set up on their own.
Self-issued Certificates and Private CA Certificates are deployed to the <data>/config/private/trusted-x509-keys
directory of Controller and Agent instances.
The article explains how to create Signing Certificates for use with JS7. Users who operate an existing Private Certificate Authority might find different approaches and different responsibilities for the indicated steps. There's more than one way how to do it.
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.
Creating self-issued Certificates
Creating the Private Key and Certificate Signing Request
The steps to create a Private Key and Certificate Signing Request are similar for self-issued Certificates and Private CA-signed Certificates.
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 key_name
environment variable with a name of their choice that is used when creating related files.
Using ECDSA Encryption
# Specify key name used for file names
key_name=signing
# Create Private Key
openssl ecparam -genkey -name secp384r1 -out ${key_name}.key
# Create Certificate Signing Request
openssl req -new -sha512 -nodes \
-key ${key_name}.key \
-out ${key_name}.csr \
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${key_name}"
Windows version...
@rem Specify key name used for file names
set key_name=signing
@rem Create Private Key
openssl ecparam -genkey -name secp384r1 -out %key_name%.key
@rem Create Certificate Signing Request
openssl req -new -sha512 -nodes ^
-key %key_name%.key ^
-out %key_name%.csr ^
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%key_name%"
Explanations...
- 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 self-issued Certificates 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 that must be different.
- The following files will be created with this step:
- The
signing.key
file will hold the Private Key. - The
signing.csr
file will hold the Certificate Signing Request.
Using RSA Encryption
Click to expand/collapse...
# Specify key name used for file names
key_name=signing
# Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes \
-keyout ${key_name}.key \
-out ${key_name}.csr \
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${key_name}"
Windows version...
@rem Specify key name used for file names
set key_name=signing
@rem Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes ^
-keyout %key_name%.key ^
-out %key_name%.csr ^
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%key_name%"
Explanations...
- In the example the Private Key is created using the specified key size
4096
. - For use of the SHA hash algorithm
-sha256
and the -subj
option see Using ECDSA Encryption. - The following files will be created with this step:
- The
signing.key
file will hold the Private Key. - The
signing.csr
file will hold the Certificate Signing Request.
Creating the Signing Certificate
Users can run the following commands from the shell and replace the value of the key_name
environment variable with a name of their choice that is used when creating related files.
# Specify key name used for file names
key_name=signing
# Create Certificate
openssl x509 -req -sha512 -days 3652 \
-signkey ${key_name}.key \
-in ${key_name}.csr \
-out ${key_name}.crt \
-extfile <(printf "keyUsage=critical,nonRepudiation,digitalSignature\nextendedKeyUsage=critical,codeSigning\n")
Windows version...
@rem Specify key name used for file names
set key_name=signing
@rem Create Certificate
set user_crt_tmp_file=user-crt-%RANDOM%.tmp
copy /Y NUL %user_crt_tmp_file%
echo keyUsage=critical,nonRepudiation,digitalSignature >> %user_crt_tmp_file%
echo extendedKeyUsage=critical,codeSigning >> %user_crt_tmp_file%
openssl x509 -req -sha512 -days 3652 ^
-signkey %key_name%.key ^
-in %key_name%.csr ^
-out %key_name%.crt ^
-extfile %user_crt_tmp_file%
del /q %user_crt_tmp_file%
Explanations...
- The SHA option such as
-sha256, -sha384, -sha512
can be freely chosen. - The
-days
argument optionally specifies the validity period of the resulting certificate. - 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 a number of extensions recommended for use with Signing Certificates. - The following files will be created with this step:
- The
signing.crt
file will hold the self-issued Certificate.
Self-issued Certificates must be copied to the <data>/config/private/trusted-x509-keys
directory of Controller and Agent instances.
Creating CA-signed Certificates
Setting up the Private CA
For Private CA-signed Certificates a Certificate Authority (CA) is required owning a CA Private Key and CA Certificate. The CA Private Key and CA Certificate will be used to sign certificates on behalf of users.
- Setup of the Certificate Authority is performed once.
- Signing is performed for each certificate on behalf of users.
The steps to create the CA Private Key and CA Certificate are similar to Creating the Private Key and Certificate Signing Request for self-issued Certificates.
Creating the Private Key and Certificate Signing Request
Steps include to create the signing-ca.key
CA Private Key file and signing-ca.csr
CA Certificate Signing Request file both 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.
Using ECDSA Encryption
# Specify key name used for file names
ca_key_name=signing-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}"
Windows version...
@rem Specify key name used for file names
set ca_key_name=signing-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%"
Using RSA Encryption
Click to expand/collapse...
# Specify key name used for file names
ca_key_name=signing-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}"
Windows version...
@rem Specify key name used for file names
set ca_key_name=signing-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%"
---
Creating the CA Certificate
Steps include to create the signing-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.
# Specify key name used for file names
ca_key_name=signing-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")
Windows version...
@rem Specify key name used for file names
set ca_key_name=signing-ca
@rem Create Certificate
set ca_crt_tmp_file=ca-crt-%RANDOM%.tmp
copy /Y NUL %ca_crt_tmp_file%
echo basicConstraints=CA:TRUE >> %ca_crt_tmp_file%
echo keyUsage=critical,nonRepudiation,keyCertSign,cRLSign >> %ca_crt_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_crt_tmp_file%
del /q %ca_crt_tmp_file%
Explanations...
- Explanations are similar to Creating self-issued Certificates with a few exceptions.
- The
-days
option specifying the validity period of the CA Certificate should be longer than the validity period of individual certificates. - 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
signing-ca.crt
file will hold the CA Certificate.
The CA Certificate must be copied to the <data>/config/private/trusted-x509-keys
directory of Controller and Agent instances.
Creating Signing Certificates
The steps explained with this section are performed for each Signing Certificate created on behalf of a user.
Creating the Private Key and Certificate Signing Request
Steps include to create the signing.key
Private Key file and signing.csr
Certificate Signing Request file both in PEM format.
Users can run the following commands from the shell and replace the value of the key_name
environment variable with a name of their choice that is used when creating related files.
Using ECDSA Encryption
# Specify key name used for file names
key_name=signing
# Create Private Key
openssl ecparam -genkey -name secp384r1 -out ${key_name}.key
# Create Certificate Signing Request
openssl req -new -sha512 -nodes \
-key ${key_name}.key \
-out ${key_name}.csr \
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${key_name}"
Windows version...
@rem Specify key name used for file names
set key_name=signing-ca
@rem Create Private Key
openssl ecparam -genkey -name secp384r1 -out %key_name%.key
@rem Create Certificate Signing Request
openssl req -new -sha512 -nodes ^
-key %key_name%.key ^
-out %key_name%.csr ^
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%key_name%"
Using RSA Encryption
Click to expand/collapse...
# Specify key name used for file names
key_name=signing
# Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes \
-keyout ${key_name}.key \
-out ${key_name}.csr \
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=${key_name}"
Windows version...
@rem Specify key name used for file names
set key_name=signing
@rem Create Private Key and Certificate Signing Request
openssl req -new -newkey rsa:4096 -sha256 -nodes ^
-keyout %key_name%.key ^
-out %key_name%.csr ^
-subj "/C=DE/ST=Berlin/L=Berlin/O=SOS/OU=IT/CN=%key_name%"
Explanations...
- In the example the Private Key is created using the specified key size
4096
. - For use of the SHA hash algorithm
-sha256
and the -subj
option see Using ECDSA Encryption. - The following files will be created with this step:
- The
signing.key
file will hold the Private Key. - The
signing.csr
file will hold the Certificate Signing Request.
Creating the Signing Certificate
Steps include to create the signing.crt
Private CA-signed Certificate file in PEM format.
Users can run the following commands from the shell and replace the value of the key_name
environment variable with a name of their choice that is used when creating related files:
# Specify key name used for file names
key_name=signing
# Create Certificate
openssl x509 -req -sha512 -days 3652 \
-CA signing-ca.crt \
-CAkey signing-ca.key \
-CAcreateserial \
-in ${key_name}.csr \
-out ${key_name}.crt \
-extfile <(printf '\nkeyUsage=critical,nonRepudiation,digitalSignature\nextendedKeyUsage=critical,codeSigning\n')
Windows version...
@rem Specify key name used for file names
set key_name=signing
@rem Create Certificate
set user_crt_tmp_file=user-crt-%RANDOM%.tmp
copy /Y NUL %user_crt_tmp_file%
echo basicConstraints=CA:TRUE >> %user_crt_tmp_file%
echo keyUsage=critical,nonRepudiation,digitalSignature >> %user_crt_tmp_file%
echo extendedKeyUsage=critical,codeSigning >> %user_crt_tmp_file%
openssl x509 -req -sha512 -days 3652 ^
-CA signing-ca.crt ^
-CAkey signing-ca.key ^
-CAcreateserial ^
-in %key_name%.csr ^
-out %key_name%.crt ^
-extfile %user_crt_tmp_file%
del /q %user_crt_tmp_file%
Explanations...
- Explanations are similar to Creating self-issued Certificates with a few exceptions:
- The
-days
option specifying the validity period of the Signing Certificate should indicate a shorter period than the validity period of the CA Certificate. - The
-CA
option specifies the location of the CA Certificate file. - The
-CAkey
option specifies the location of the CA Private Key file. - The
-in
option specifies the location of the Certificate Signing Request. - The
-extfile
option specifies the Key Usage and Extended Key Usage being limited to code signing.
- The following files will be created with this step:
- The
signing.crt
file will hold the Signing Certificate.
The Signing Certificate file does not require to be deployed to Controller and Agent instances. Instead, the CA Certificate file is deployed to Controller and Agent instances.
Further Resources