Introduction

JS7 - Deployment of Scheduling Objects makes use of signing certificates to digitally sign workflows and other objects. Use of certificates for signing is not related to use of certificates to secure connections such as HTTPS.

• Certificates for the specific use of code signing should be used.
• Users choose which approach they want to follow:
  • Creating self-signed certificates.
  • Creating CA-signed certificates.

Rollout of certificates to Controllers and Agents depends on the following choice:

• Self-signed certificates have to be deployed from individual certificate files made available for Controllers and Agents.
  • There is no security gap in use of self-signed certificates. When users store certificate files to Controllers and Agents then this proves that they trust the certificates.
• CA-signed certificates usually are not deployed. Instead, the CA Certificate is deployed that was used to sign individual 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 Signing CA.

Creating self-signed Certificates

Users have an option ot use ECDSA or RSA for the encryption type.

Users can run the following commands from a bash 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

# Step 1 - Generate Private Key
openssl ecparam -name secp256k1 -genkey -noout -out ${key_name}.key

# Step 2 - Generate and sign Certificate
openssl req -new -x509 -sha256 -key ${key_name}.key -out ${key_name}.crt -days 5475

Explanation:

• Step 1: The Private Key is created.
  
  • Choice of algorithm such as secp256k1 is up to the user.
  • The <key_name>.key file will hold the Private Key.
• Step 2: The Certificate is created.
  • The -days argument optionally specifies the validity period of the Certificate.
  • The <key_name>.crt file will hold the self-signed Certificate.

Using RSA Encryption

# Specify key name used for file names
key_name=signing

# Generate Private Key and Certificate
openssl req -x509 -sha256 -newkey rsa:4096 -nodes -keyout ${key_name}.key -out ${key_name}.crt -days 5475

Explanation:

• In the example the Private Key is created using the specified key size of 4096.
• The Certificate is created with the -days argument optionally specified for the validity period of the Certificate.
• The <key_name>.key file will hold the Private Key.
• The <key_name>.crt file will hold the self-signed Certificate.

Creating CA-signed Certificates

Creating the Signing CA Certificate

Steps include to create the signing-ca.key Private Key file and signing-ca.crt self-signed Certificate file for the Signing CA both in PEM format.

# Step 1: Generate Signing Certificate Authority (CA) Private Key
openssl ecparam -genkey -name secp256k1 -noout -out signing-ca.key
 
# Step 2: Generate Signing CA Certificate
openssl req -new -x509 -sha256 -days 5475 -key signing-ca.key -out signing-ca.crt

# 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) [XX]:DE
# State or Province Name (full name) []:Berlin
# Locality Name (eg, city) [Default City]:Berlin
# Organization Name (eg, company) [Default Company Ltd]:SOS
# Organizational Unit Name (eg, section) []:JS7
# Common Name (eg, your name or your server's hostname) []:JS7 Deployment CA
# Email Address []:

# Step 1: Generate Signing Certificate Authority (CA) Private Key using passphrase
openssl ecparam -genkey -name secp256k1 | openssl ec -aes256 -passout pass:"jobscheduler" -out signing-ca.key

 # Step 2: Generate Signing CA Certificate
openssl req -new -x509 -sha256 -days 5475 -key signing-ca.key -passin pass:"jobscheduler" -out signing-ca.crt

Explanation:

• Step 1: The Private Key is created.
  
  • Choice of algorithm such as secp256k1 is up to the user.
  • The signing-ca.key file will hold the Private Key.
• Step 2: The Signing CA Certificate is created
  
  • As a response to the command the OpenSSL utility prompts for a number of specifications for the Distinguished Name, i.e. the unique name of the Signing CA Certificate: 
    • Country Name: a 2 letter country code is expected as stated for example with https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2
    • State or Province Name: the name of a state is expected
    • Locality Name:  the name of a city is expected
    • Organization Name: arbitrary input is allowed
    • Organizational Unit Name: arbitrary input is allowed
    • Common Name: an arbitrary name can be chosen as the name of the Signing CA
    • Email Address: empty input is allowed
  • The signing-ca.crt file will hold the Signing Certificate..

Creating a Signing Certificate

For a new signing certificate the steps include to create the Private Key and Certificate Signing Request (CSR). The resulting Signing Certificate will be signed by the Signing CA.

Users can run the following commands from a bash 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

# Step 1 - Generate Private Key and Certificate Signing Request
openssl req -new -sha256 -config <(cat openssl-cert.config <(printf "\n[SAN]\nnsCertType = objsign\nkeyUsage = critical, nonRepudiation, digitalSignature, keyEncipherment\n\nextendedKeyUsage = critical, codeSigning\n\nsubjectKeyIdentifier = hash\n")) \
	-nodes -keyout ${key_name}.key -out ${key_name}.csr

# Step 2 - Generate and sign the Signing Certificate
openssl x509 -req \
    -in ${key_name}.csr \
    -CA signing-ca.crt \
    -CAkey signing-ca.key \
    -CAcreateserial \
    -out ${key_name}.crt -days 7300 \
    -extfile <(printf 'nsCertType = objsign\nkeyUsage = critical, nonRepudiation, digitalSignature, keyEncipherment\n\n\nextendedKeyUsage = critical, codeSigning\n\nsubjectKeyIdentifier = hash\n' "${key_name}")

Explanation:

• Step 1: Create Private Key and Certificate Signing Request
  • The Certificate Signing Request is created for the Key Usage and Extended Key Usage as indicated.
  • The following files will be created for the given server:
    • <key_name>.key: the Private Key
    • <key_name>.csr: the Certificate Signing Request
• Step 2: The Signing Certificate is created.
  • The following files will be created:
    • <key_name>.crt: the Signing Certificate

In order to run the script successfully the following openssl-cert.config file has to be present. To create a Signing Certificate the CommonName attribute has to be adjusted.

• Download: openssl-cert.config
• Replace the value of the commonName attribute with the name of an account or user for which the certificate should be created.
• Adjust other attributes in the [ standard_dn ] section to your needs.
  
  

[ req ]
prompt             = no
distinguished_name = standard dn

[ standard dn ]
           countryName = DE
   stateOrProvinceName = Berlin
          localityName = Berlin
      organizationName = SOS
organizationalUnitName = IT
            commonName = signing

[ standard exts ]
keyUsage = critical, nonRepudiation, digitalSignature

# see x509v3_config for other extensions