Deploy custom certificate

Note

Only available on Enterprise plans.

Enterprise customers who do not wish to install a Cloudflare certificate have the option to upload their own root certificate to Cloudflare. This feature is sometimes referred to as Bring Your Own Public Key Infrastructure (BYOPKI). Gateway will use your uploaded certificate to encrypt all sessions between the end user and Gateway, enabling all HTTPS inspection features that previously required a Cloudflare certificate. You can upload multiple certificates to your account, but only one can be active at any given time. You also need to upload a private key to intercept domains with JIT certificates and to enable the block page.

You can upload up to five custom root certificates. If your organization requires more than five certificates, contact your account team.

Warning

Custom certificates are limited to use between your users and the Gateway proxy. Connections between Gateway and the origin server will use a Cloudflare certificate.

Generate a custom root CA

Before you generate a custom root CA, make sure you have OpenSSL ↗ installed.

1. Open a terminal.

2. Create a directory for the root CA and change into it.

   mkdir -p /root/customca
   cd /root/customca

3. Generate a private key for the root CA.

   openssl genrsa -out <CUSTOM-ROOT-PRIVATE-KEY>.pem 2048

4. Generate a self-signed root certificate.

   openssl req -x509 -sha256 -new -nodes -key <CUSTOM-ROOT-PRIVATE-KEY>.pem -days 365 -out <CUSTOM-ROOT-CERT>.pem

When preparing your certificate and private key for upload, be sure to remove any unwanted characters, such as mismatching subdomains in the certificate’s common name. To review the private key, run the following command:

openssl rsa -in <CUSTOM-ROOT-PRIVATE-KEY>.pem -text

To review the certificate, run the following command:

openssl x509 -in <CUSTOM-ROOT-CERT>.pem -text

Deploy a custom root certificate

Dashboard

1. In Zero Trust ↗, go to Settings > Resources.
2. In Certificates, select Manage.
3. Select Upload certificate.
4. Enter the private key and SSL certificate you generated or select Paste certificate from file to upload them from a file.
5. Select Generate certificate.

You can now use the generated custom root certificate for inspection.

API

1. Verify that the certificate is installed on your devices.

2. Use the Upload mTLS certificate endpoint to upload the certificate and private key to Cloudflare. The certificate must be a root CA, formatted as a single string with \n replacing the line breaks.

   curl "https://api.cloudflare.com/client/v4/accounts/{account_id}/mtls_certificates" \
   --header "X-Auth-Email: <EMAIL>" \
   --header "X-Auth-Key: <API_KEY>" \
   --header "Content-Type: application/json" \
   --data '{
     "name": "example_ca_cert",
     "certificates": "-----BEGIN CERTIFICATE-----\nXXXXX\n-----END CERTIFICATE-----",
     "private_key": "-----BEGIN PRIVATE KEY-----\nXXXXX\n-----END PRIVATE KEY-----",
     "ca": true
   }'

   The response will return a UUID for the certificate. For example:

   {
     "success": true,
     "errors": [],
     "messages": [],
     "result": {
       "id": "2458ce5a-0c35-4c7f-82c7-8e9487d3ff60",
       "name": "example_ca_cert",
       "issuer": "O=Example Inc.,L=California,ST=San Francisco,C=US",
       "signature": "SHA256WithRSA"
       ...
     }
   }

3. Deploy the certificate in Gateway using the certificate’s UUID with the Patch Zero Trust account configuration endpoint.

   curl --request PATCH \
   "https://api.cloudflare.com/client/v4/accounts/{account_id}/gateway/configuration" \
   --header "X-Auth-Email: <EMAIL>" \
   --header "X-Auth-Key: <API_KEY>" \
   --header "Content-Type: application/json" \
   --data '{
     "settings": {
       "custom_certificate": {
         "enabled": true,
         "id": "2458ce5a-0c35-4c7f-82c7-8e9487d3ff60"
       }
     }
   }'

   The response will return the pending status of the certificate. For example:

   {
     "success": true,
     "errors": [],
     "messages": [],
     "result": {
       "settings": {
         "antivirus": {},
         "block_page": {},
         "custom_certificate":
           {
             "enabled": true,
             "id": "2458ce5a-0c35-4c7f-82c7-8e9487d3ff60",
             "binding_status": "pending_deployment",
             "qs_pack_id": "50a78g31-a5b5-4k58d-a6ed-b0ac17da9k05"
           },
         "tls_decrypt": {},
         "activity_log": {},
         "browser_isolation": {},
         "fips": {},
       },
     },
     "created_at": "2014-01-01T05:20:00.12345Z",
     "updated_at": "2014-01-01T05:20:00.12345Z"
   }

4. Activate the certificate for use in inspection with the Activate a Zero Trust certificate endpoint.

   curl --request POST \
   "https://api.cloudflare.com/client/v4/accounts/{account_id}/gateway/certificates/{certificate_id}/activate" \
   --header "X-Auth-Email: <EMAIL>" \
   --header "X-Auth-Key: <API_KEY>"

   The response will return the certificate and its current deployment status. For example:

   {
     "errors": [],
     "messages": [],
     "success": true,
     "result": {
       "binding_status": "active",
       "certificate": "-----BEGIN CERTIFICATE-----\\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\\n-----END CERTIFICATE-----\\n",
       "created_at": "2014-01-01T05:20:00.12345Z",
       "expires_on": "2014-01-01T05:20:00.12345Z",
       "fingerprint": "E9:19:49:AA:DD:D8:1E:C1:20:2A:D8:22:BF:A5:F8:FC:1A:F7:10:9F:C7:5B:69:AB:0:31:91:8B:61:B4:BF:1C",
       "id": "f174e90a-fafe-4643-bbbc-4a0ed4fc8415",
       "in_use": true,
       "issuer_org": "Example Inc.",
       "issuer_raw": "O=Example Inc.,L=California,ST=San Francisco,C=US",
       "type": "gateway_managed",
       "updated_at": "2014-01-01T05:20:00.12345Z",
       "uploaded_on": "2014-01-01T05:20:00.12345Z"
     }
   }

Once binding_status changes to active, Gateway will sign your traffic using the custom root certificate and private key. If you disable the custom certificate, Gateway will revert to the default Cloudflare certificate generated for your Zero Trust account.

Private key visibility

When you upload a private key to Zero Trust, Cloudflare encrypts the key and stores it at rest. Only your delegated apps have the necessary decryption keys to decrypt the private key. You will not be able to retrieve the private key after upload.

Use a custom root certificate

To use a custom root certificate you generated and uploaded to Cloudflare, refer to Activate a root certificate.

Troubleshoot HTTP errors

If Gateway returns an HTTP Response Code: 526 after deploying a custom certificate, you can troubleshoot errors with our FAQ.