Internal CA

graph TD
    A[Root CA]
    A --> B[Intermediate CA]
    A --> C[Intermediate CA]

    Go to **Certificate Manager → Certificate Authorities → Internal** and click **Create CA**.

    Set the **CA Type** to **Root** and fill out details for the root CA:


    - Valid Until: The date until which the CA is valid in the date time string format specified [here](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#date_time_string_format). For example, the following formats would be valid: `YYYY`, `YYYY-MM`, `YYYY-MM-DD`, `YYYY-MM-DDTHH:mm:ss.sssZ`.
    - Path Length: The maximum number of intermediate CAs that can be chained to this CA. A path of `-1` implies no limit; a path of `0` implies no intermediate CAs can be chained.
    - Key Algorithm: The type of public key algorithm and size, in bits, of the key pair that the CA creates when it issues a certificate. Supported key algorithms are `RSA 2048`, `RSA 4096`, `ECDSA P-256`, and `ECDSA P-384` with the default being `RSA 2048`.
    - Name: A slug-friendly name for the CA.
    - Organization (O): The organization name.
    - Country (C): The country code.
    - State or Province Name: The state or province.
    - Locality Name: The city or locality.
    - Common Name: The name of the CA.

    <Note>
        The Organization, Country, State or Province Name, Locality Name, and Common Name make up the **Distinguished Name (DN)** or **subject** of the CA.
        At least one of these fields must be filled out.
    </Note>
</Step>
<Step title="Creating an intermediate CA">
    To create an intermediate CA, press **Create CA** again but this time specifying the **CA Type** to be **Intermediate**. Fill out the details for the intermediate CA.

    Next, press the **Install CA Certificate** option on the intermediate CA. You will be presented with the installation method selector. Choose how the signing certificate should be issued:

    <Tabs>
      <Tab title="Infisical CA">
        Select **Infisical CA** and press **Continue**. This option chains the intermediate CA to a root or intermediate CA managed by Infisical.

        Set the **Parent CA** to the root CA created in step 1 and configure:
        - **Parent CA**: The parent CA to chain to (the root CA from step 1).
        - **Valid Until**: Must be within the validity period of the parent CA.
        - **Path Length**: Must be less than the parent CA's path length.

        Press **Install** to chain the intermediate CA to the root CA. This creates a CSR, signs it with the root CA, and imports the certificate.

        You've successfully created a Private CA hierarchy. Now check out the [Applications section](/documentation/platform/pki/applications/overview) to learn more about issuing certificates.
      </Tab>
      <Tab title="Manual">
        Select **Manual** and press **Continue**. This option allows you to sign the intermediate CA certificate using an external root CA that you manage outside of Infisical.

        Use the provided CSR to generate a certificate from your external root CA. Paste the PEM-encoded certificate into **Certificate Body** and the root CA certificate into **Certificate Chain**.

        Press **Install** to import the certificate.

        You've successfully created a Private CA hierarchy with an intermediate CA chained to an external root CA. Now check out the [Applications section](/documentation/platform/pki/applications/overview) to learn more about issuing certificates.
      </Tab>
      <Tab title="External CA">
        Select **External CA (Automated)** and press **Continue**. This option connects to a third-party CA provider to handle certificate signing and renewal automatically via API.

        Infisical currently supports the following external CA providers for signing intermediate CAs:

        - [Venafi TLS Protect Cloud](/documentation/platform/pki/ca/venafi)
        - [Azure AD CS](/documentation/platform/pki/ca/azure-adcs#signing-internal-intermediate-cas-with-ad-cs)

        <Note>
          When using an external CA, the certificate issued by the provider **must** correspond to the CSR generated by Infisical.
          If the external CA returns a certificate that does not match the CSR (e.g., different subject or key), the installation will fail.
        </Note>

        Refer to the provider-specific documentation linked above for detailed setup and installation instructions.
      </Tab>
    </Tabs>

To create a root CA, make an API request to the [Create CA](/api-reference/endpoints/certificate-authorities/create) API endpoint, specifying the `type` as `root`.

### Sample request

```bash Request
curl --location --request POST 'https://app.infisical.com/api/v1/cert-manager/ca/internal' \
  --header 'Authorization: Bearer <access-token>' \
  --header 'Content-Type: application/json' \
  --data-raw '{
      "type": "root",
      "commonName": "My Root CA"
  }'
```

### Sample response

```bash Response
{
  ca: {
    id: "<root-ca-id>",
    type: "root",
    commonName: "My Root CA",
    ...
  }
}
```

By default, Infisical creates a root CA with the `RSA_2048` key algorithm, validity period of 10 years, with no restrictions on path length;
you may override these defaults by specifying your own options when making the API request.

### Sample request

```bash Request
curl --location --request POST ‘https://app.infisical.com/api/v1/cert-manager/ca/internal’ \
  --header ‘Authorization: Bearer <access-token>’ \
  --header ‘Content-Type: application/json’ \
  --data-raw ‘{
      "type": "intermediate",
      "commonName": "My Intermediate CA"
  }’
```

### Sample response

```json Response
{
  "ca": {
    "id": "<intermediate-ca-id>",
    "type": "intermediate",
    "commonName": "My Intermediate CA"
  }
}
```

Next, install a certificate for the intermediate CA using one of the following methods:

<Tabs>
  <Tab title="Infisical CA">
    Get a CSR from the intermediate CA, sign it with the root CA, and import the certificate back.

    **Get the CSR:**

    ```bash Request
    curl --location --request GET ‘https://app.infisical.com/api/v1/cert-manager/ca/internal/<intermediate-ca-id>/csr’ \
      --header ‘Authorization: Bearer <access-token>’
    ```

    **Sign the intermediate certificate using the root CA:**

    ```bash Request
    curl --location --request POST ‘https://app.infisical.com/api/v1/cert-manager/ca/internal/<root-ca-id>/sign-intermediate’ \
      --header ‘Authorization: Bearer <access-token>’ \
      --header ‘Content-Type: application/json’ \
      --data-raw ‘{
          "csr": "<csr>",
          "notAfter": "2029-06-12"
      }’
    ```

    <Note>
      The `notAfter` value must be within the validity period of the root CA.
    </Note>

    **Import the signed certificate back to the intermediate CA:**

    ```bash Request
    curl --location --request POST ‘https://app.infisical.com/api/v1/cert-manager/ca/internal/<intermediate-ca-id>/import-certificate’ \
      --header ‘Authorization: Bearer <access-token>’ \
      --header ‘Content-Type: application/json’ \
      --data-raw ‘{
          "certificate": "<certificate>",
          "certificateChain": "<certificate-chain>"
      }’
    ```

    You’ve successfully created a Private CA hierarchy. Now check out the [Applications](/documentation/platform/pki/applications/overview) page to learn more about issuing certificates.
  </Tab>
  <Tab title="Manual">
    Get the CSR from the intermediate CA and use it to generate a certificate from your external root CA.

    **Get the CSR:**

    ```bash Request
    curl --location --request GET ‘https://app.infisical.com/api/v1/cert-manager/ca/internal/<intermediate-ca-id>/csr’ \
      --header ‘Authorization: Bearer <access-token>’
    ```

    Use this CSR with your external root CA to generate a signed certificate. Then import the certificate and chain back:

    ```bash Request
    curl --location --request POST ‘https://app.infisical.com/api/v1/cert-manager/ca/internal/<intermediate-ca-id>/import-certificate’ \
      --header ‘Authorization: Bearer <access-token>’ \
      --header ‘Content-Type: application/json’ \
      --data-raw ‘{
          "certificate": "<certificate-from-external-ca>",
          "certificateChain": "<external-root-ca-certificate>"
      }’
    ```

    You’ve successfully chained an intermediate CA to an external root CA. Now check out the [Applications](/documentation/platform/pki/applications/overview) page to learn more about issuing certificates.
  </Tab>
  <Tab title="External CA">
    You can use an external CA provider to automatically sign the intermediate CA certificate via API. See the provider-specific documentation for the full API workflow:

    - [Venafi TLS Protect Cloud](/documentation/platform/pki/ca/venafi)
    - [Azure AD CS](/documentation/platform/pki/ca/azure-adcs#signing-internal-intermediate-cas-with-ad-cs)

    <Note>
      When using an external CA, the certificate issued by the provider **must** correspond to the CSR generated by Infisical.
      If the external CA returns a certificate that does not match the CSR, the installation will fail.
    </Note>
  </Tab>
</Tabs>