--- title: "Internal CA" sidebarTitle: "Internal CA" description: "Learn how to create a Private CA hierarchy with Infisical." --- ## Concept Infisical lets you build your Internal PKI through a Private Certificate Authority (CA) hierarchy, enabling you to issue and manage digital certificates for your end-entities.
```mermaid graph TD A[Root CA] A --> B[Intermediate CA] A --> C[Intermediate CA] ```
## Workflow A typical workflow for setting up a Private CA hierarchy consists of the following steps: 1. Configuring an Infisical root CA with details like name, validity period, and path length — This step is optional if you wish to use an external root CA with Infisical only serving the intermediate CAs. 2. Configuring and chaining intermediate CA(s) with details like name, validity period, path length, and imported certificate to your Root CA. 3. Managing the CA lifecycle events such as CA succession. Note that this workflow can be executed via the Infisical UI or manually such as via API. If manually executing the workflow, you may have to create a Certificate Signing Request (CSR) for the intermediate CA, create an intermediate certificate using the root CA private key and CSR, and import the intermediate certificate back to the intermediate CA as part of Step 2. ## Guide to Creating a CA Hierarchy In the following steps, we explore how to create a simple Private CA hierarchy consisting of an (optional) root CA and an intermediate CA. If you wish to use an external root CA, you can skip this step and head to step 2 to create an intermediate CA. To create a root CA, head to your Certificate Management Project > Certificate Authorities > Internal Certificate Authorities and press **Create CA**. ![pki create ca](/images/platform/pki/ca/ca-create.png) Here, set the **CA Type** to **Root** and fill out details for the root CA. ![pki create root ca](/images/platform/pki/ca/ca-create-root.png) Here's some guidance for each field: - 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. 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. 2.1. 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. ![pki create intermediate ca](/images/platform/pki/ca/ca-create-intermediate.png) 2.2. Next, press the **Install Certificate** option on the intermediate CA from step 1.1. ![pki install cert opt](/images/platform/pki/ca/ca-install-intermediate-opt.png) 2.3a. If you created a root CA in step 1, select **Infisical CA** for the **Parent CA Type** field. Next, set the **Parent CA** to the root CA created in step 1 and configure the intended **Valid Until** and **Path Length** fields on the intermediate CA; feel free to use the prefilled values. ![pki install cert](/images/platform/pki/ca/ca-install-intermediate.png) Here's some guidance on each field: - Parent CA: The parent CA to which this intermediate CA will be chained. In this case, it should be the root CA created in step 1. - 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). The date must be within the validity period of the parent CA. - Path Length: The maximum number of intermediate CAs that can be chained to this CA. The path length must be less than the path length of the parent CA. Finally, press **Install** to chain the intermediate CA to the root CA; this creates a Certificate Signing Request (CSR) for the intermediate CA, creates an intermediate certificate using the root CA private key and CSR, and imports the signed certificate back to the intermediate CA. ![pki cas](/images/platform/pki/ca/cas.png) Great! You've successfully created a Private CA hierarchy with a root CA and an intermediate CA. Now check out the [Certificates section](/documentation/platform/pki/certificates/overview) to learn more about how to issue X.509 certificates using the intermediate CA. 2.3b. If you have an external root CA, select **External CA** for the **Parent CA Type** field. Next, use the provided intermediate CSR to generate a certificate from your external root CA and paste the PEM-encoded certificate back into the **Certificate Body** field; the PEM-encoded external root CA certificate should be pasted under the **Certificate Chain** field. ![pki ca csr](/images/platform/pki/ca/ca-install-intermediate-csr.png) Finally, press **Install** to import the certificate and certificate chain as part of the installation step for the intermediate CA Great! You've successfully created a Private CA hierarchy with an intermediate CA chained to an external root CA. Now check out the [Certificates section](/documentation/platform/pki/certificates/overview) to learn more about how to issue X.509 certificates using the intermediate CA. If you wish to use an external root CA, you can skip this step and head to step 2 to create an intermediate CA. 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/pki/ca' \ --header 'Authorization: Bearer ' \ --header 'Content-Type: application/json' \ --data-raw '{ "projectSlug": "", "type": "root", "commonName": "My Root CA" }' ``` ### Sample response ```bash Response { 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. 2.1. To create an intermediate CA, make an API request to the [Create CA](/api-reference/endpoints/certificate-authorities/create) API endpoint, specifying the `type` as `intermediate`. ### Sample request ```bash Request curl --location --request POST 'https://app.infisical.com/api/v1/pki/ca' \ --header 'Authorization: Bearer ' \ --header 'Content-Type: application/json' \ --data-raw '{ "projectSlug": "", "type": "intermediate", "commonName": "My Intermediate CA" }' ``` ### Sample response ```bash Response { ca: { id: "", type: "intermediate", commonName: "My Intermediate CA", ... } } ``` 2.2. Next, get a certificate signing request from the intermediate CA by making an API request to the [Get CSR](/api-reference/endpoints/certificate-authorities/csr) API endpoint. ### Sample request ```bash Request curl --location --request GET 'https://app.infisical.com/api/v1/pki/ca//csr' \ --header 'Authorization: Bearer ' \ --data-raw '' ``` ### Sample response ```bash Response { csr: "..." } ``` If using an external root CA, then use the CSR to generate a certificate for the intermediate CA using your external root CA and skip to step 2.4. 2.3. Next, create an intermediate certificate by making an API request to the [Sign Intermediate](/api-reference/endpoints/certificate-authorities/sign-intermediate) API endpoint containing the CSR from step 2.2, referencing the root CA created in step 1. ### Sample request ```bash Request curl --location --request POST 'https://app.infisical.com/api/v1/pki/ca//sign-intermediate' \ --header 'Content-Type: application/json' \ --data-raw '{ "csr": "", "notAfter": "2029-06-12" }' ``` ### Sample response ```bash Response { certificate: "...", certificateChain: "...", issuingCaCertificate: "...", serialNumber: "...", } ``` The `notAfter` value must be within the validity period of the root CA that is if the root CA is valid until `2029-06-12`, the intermediate CA must be valid until a date before `2029-06-12`. 2.4. Finally, import the intermediate certificate and certificate chain from step 2.3 back to the intermediate CA by making an API request to the [Import Certificate](/api-reference/endpoints/certificate-authorities/import-cert) API endpoint. If using an external root CA, then import the generated certificate and root CA certificate under certificate chain back into the intermediate CA. ### Sample request ```bash Request curl --location --request POST 'https://app.infisical.com/api/v1/pki/ca//import-certificate' \ --header 'Authorization: Bearer ' \ --header 'Content-Type: application/json' \ --data-raw '{ "certificate": "", "certificateChain": "" }' ``` ### Sample response ```bash Response { message: "Successfully imported certificate to CA", caId: "..." } ``` Great! You’ve successfully created a Private CA hierarchy with a root CA and an intermediate CA. Now check out the [Subscribers](/documentation/platform/pki/subscribers) page to learn more about how to issue X.509 certificates using the intermediate CA. ## Guide to CA Renewal In the following steps, we explore how to renew a CA certificate. If renewing an intermediate CA chained to an Infisical CA, then Infisical will automate the process of generating a new certificate for the intermediate CA for you. If renewing an intermediate CA chained to an external parent CA, you'll be required to generate a new certificate from the external parent CA and manually import the certificate back to the intermediate CA. Head to the CA Page of the CA you wish you renew and press **Renew CA** on the left side. ![pki ca renewal page](/images/platform/pki/ca-renewal-page.png) Input a new **Valid Until** date to be used for the renewed CA certificate and press **Renew** to renew the CA. ![pki ca renewal. modal](/images/platform/pki/ca-renewal-modal.png) The new **Valid Until** date must be within the validity period of the parent CA. To renew a CA certificate, make an API request to the [Renew CA](/api-reference/endpoints/certificate-authorities/renew) API endpoint, specifying the new `notAfter` date for the CA. ### Sample request ```bash Request curl --location --request POST 'https://app.infisical.com/api/v1/pki/ca//renew' \ --header 'Authorization: Bearer ' \ --header 'Content-Type: application/json' \ --data-raw '{ "type": "existing", "notAfter": "2029-06-12" }' ``` ### Sample response ```bash Response { certificate: "...", certificateChain: "...", serialNumber: "..." } ``` ## FAQ Infisical supports `RSA 2048`, `RSA 4096`, `ECDSA P-256`, `ECDSA P-384` key algorithms specified at the time of creating a CA. At the moment, Infisical only supports CA renewal via same key pair. We anticipate supporting CA renewal via new key pair in the coming month. Yes. You may obtain a CSR from the Intermediate CA and use it to generate a certificate from your external CA. The certificate, along with the external CA certificate chain, can be imported back to the Intermediate CA as part of the CA installation step.