TrueNAS SCALETrueNAS SCALE Nightly Development Documentation
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Certificates Authorities Screens

The Certificate Authorities widget on the Credentials > Certificates screen displays certificate authorities(CAs) added to SCALE, and allows you to add new CAs, or download, delete, or edit the name of an existing CA.


The download icon downloads the CA to your server.

delete deletes the CA from your server.

Each CA listed on the widget is a link that opens the Edit CA screen.

Add opens the Add CA wizard that steps you through setting up a certificate authority (CA) that certifies the ownership of a public key by the named subject of the certificate.

Add CA Wizard Screens

The Add CA wizard screens step users through configuring a new certificate authority on TrueNAS SCALE. The wizard has five different configuration screens, one for each step in the CA configuration process:

1 Identifier and Type

2 Certificate Options

3 Certificate Subject

4 Extra Constraints

5 Confirm Options

Identifier and Type Options

The Identifier and Type options specify the CA name and choose whether to create a new CA or import an existing CA.
Users can also select a predefined certificate extension from the Profiles dropdown list.

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The selection in Type changes setting options on this screen, the Certificate Options and Extra Constraints screens, and determines if the Certificate Subject screen displays at all.


NameRequired. Enter a descriptive identifier for this certificate authority(CA).
TypeSelect the type of CA from the dropdown list. Options are Internal CA, Intermediate CA, and Import CA. Internal CA functions like a publicly trusted CA to sign certificates for an internal network. They are not trusted outside the private network. Intermediate CA lives between the root and end entity certificates and its main purpose is to define and authorize the types of certificates you can request from the root CA. Import CA allows you to import an existing CA onto the system. For more information see What are Subordinate CAs and Why Would You Want Your Own?.
ProfilesDisplays if Internal CA or Intermediate CA are set in Type. Select a predefined certificate extension from the dropdown list. Choose a profile that best matches your certificate usage scenario. Options are Openvpn Root CA and CA.

Certificate Options

The Certificate Options settings specify the type of private key to use (as well as the number of bits in the key used by the cryptographic algorithm), the cryptographic algorithm the CA uses, and how many days the CA lasts.

The Certificate Options settings do not display if Type on the Identifier and Type screen is set to Import CA.

The Key Type selection changes fields displayed. RSA is the default setting in Key Type.

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Key TypeSelect the key type from the dropdown list. Options are RSA or EC. RSA displays the Key Length field. EC displays the EC Curve field. See Why is elliptic curve cryptography not widely used, compared to RSA? for more information about key types.
EC CurveDisplays when EC is selected in Key Type. Select the curve type from the dropdown list. Options are BrainpoolP512R1, BrainpoolP384R1, BrainpoolP256R1, SECP256K1, SECP384R1, SECP521R1, and ed25519. Brainpool curves can be more secure while SECP curves can be faster. See Elliptic Curve performance: NIST vs Brainpool for more information.
Key LengthRequired. Displays when RSA is selected in Key Type. Select the number of bits in the key used by the cryptographic algorithm from the dropdown list. Options are 1024, 2048 or 4096. For security reasons, a minimum key length of 2048 is recommended.
Digest AlgorithmSelect the cryptographic algorithm to use from the dropdown list.Options are SHA1, SHA224, SHA256, SHA384 and SHA512. Only change the default SHA256 if the organization requires a different algorithm.
LifetimeEnter the number of days for the lifetime of the CA.

Certificate Subject Options

The Certificate Subject settings define the location, name, and email for the organization using the certificate.
Users can also enter the system fully-qualified hostname (FQDN) and any additional domains for multi-domain support.

The Certificate Subject settings do not display if Type on the Identifier and Type screen is set to Import CA.

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CountryRequired. Select the country of the organization from the dropdown list.
StateRequired. Enter the state or province of the organization.
LocalityRequired. Enter the location of the organization. For example, the city.
OrganizationRequired. Enter the name of the company or organization.
Organizational UnitEnter the organizational unit of the entity.
EmailRequired. Enter the email address of the person responsible for the CA.
Common NameEnter the fully qualified host name (FQHN) of the system. This name must be unique within a certificate chain.
Subject Alternate NamesRequired. Enter additional domains to secure for multi-domain support. Separate each domain by pressing Enter. For example, if the primary domain is, entering secures both addresses.

Extra Constraints Options

The Extra Constraints options contain certificate extension options.

  • Basic Constraints that when enabled limits the path length for a certificate chain.
  • Authority Key Identifier that when enabled provides a means of identifying the public key corresponding to the private key used to sign a certificate.
  • Key Usage that when enable defines the purpose of the public key contained in a certificate.
  • Extended Key Usage that when enable to further refines key usage extensions.

The Extra Constraints settings change based on the selection in Type on the Identifier and Type screen.

Extra Constraints - Internal or Intermediate CA

After selecting Basic Constraints, Authority Key Identifier, Extended Key Usage, or Key Usage, each displays more settings that option needs.

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Basic ConstraintsSelect to activate this extension.
Path LengthDisplays after selecting Basic Constraints. Enter the number of non-self-issued intermediate certificates that can follow this certificate in a valid certification path. Entering 0 allows a single additional certificate to follow in the certificate path. Value cannot be less than 0.
Basic Constraints ConfigSelect the option to specify the extension type from the dropdown list. Options are CA and Critical Extension. The basic constraints extension identifies whether the subject of the certificate is a CA and the maximum depth of valid certification paths that include this certificate. See RFC 3280, section 4.2.10 for more information.
Authority Key IdentifierSelect to activate this extension. Displays the Authority Key Config field.
Authority Key ConfigDisplays after selecting Authority Key Identifier. Select the option to specify whether the authority key identifier extension provides a means of identifying the public key corresponding to the private key used to sign a certificate. Options are Authority Cert Issuer and or Critical Extension. This extension is used where an issuer has multiple signing keys (either due to multiple concurrent key pairs or due to changeover). The identification might be based on either the key identifier (the subject key identifier in the issuer certificate) or on the issuer name and serial number. See RFC 3280, section for more information.
Extended Key UsageSelect to activate this certificate extension. Displays the Usages field.
UsagesDisplays after selecting Extended Key Usage. Select the option to identify the purpose of this public key from the dropdown list. Typically used for the end entity certificates. You can select multiple usages that display separated by a comma (,). Options are ANY_EXTENDED_KEY_USAGE, CLIENT_AUTH, CODE_SIGNING, EMAIL_PROTECTION, OCSP_SIGNING, SERVER_AUTH, or TIME_STAMPING. Do not mark this extension critical when set to ANY_EXTENDED_KEY_USAGE. Using both Extended Key Usage and Key Usage extensions requires that the purpose of the certificate is consistent with both extensions. See RFC 3280, section 4.2.13 for more details.
Critical ExtensionDisplays after selecting Extended Key Usage. Select to identify this extension as critical for the certificate. The certificate-using system must recognize critical extensions or this certificate is rejected. T he certificate-using system can ignore the extensions identified as not critical and still approve the certificate.
Key UsageSelect to activate this certificate extension. Displays the Key Usage Config field.
Key Usage ConfigDisplays after selecting Extended Key Usage or Key Usage. Select the key usage extension from the dropdown list. Options are Digital Signature, Content Commitment, Key Encipherment, Data Encipherment, Key Agreement, Key Cert Sign, CRL Sign, Encipher Only, Decipher Only or Critical Extension. The key usage extension defines the purpose (e.g., encipherment, signature, certificate signing) of the key contained in the certificate. The usage restriction might be employed when a key that could be used for more than one operation is to be restricted. For example, when an RSA key should be used only to verify signatures on objects other than public key certificates and CRLs, the Digital Signature bits would be asserted. Likewise, when an RSA key should be used only for key management, the Key Encipherment bit would be asserted.

See RFC 3280, section for more information.

Import Certificate

When Type on Identifier and Type is set to Import CA the Import Certificate screen displays.

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CertificateRequired. Paste the certificate for the CA into this field.
Private KeyRequired. Paste the private key associated with the certificate when available. Provide a key at least 1024 bits long.
PassphraseEnter the passphrase for the private key.
Confirm PassphraseRe-enter the passphrase for the private key.

Confirm Options

The final step screen is the Confirm Options that displays the CA Type, Key Type, Key Length, Digest Algorithm, Lifetime, Country, and any configured Usages. For Import CA type, the screen displays Type and Certificate.


Save adds the certificate to SCALE. Back returns to previous screens to make changes before you save. Next advances to the next screen in the sequence to return to Confirm Options.