Self-signed certificate for SSL/TLS


If your Home Assistant instance is only accessible from your local network you can still protect the communication between your browsers and the frontend with SSL/TLS. Let’s encrypt will only work if you have a DNS entry and remote access is allowed. The solution is to use a self-signed certificate. As you most likely don’t have a certification authority (CA) your browser will complain about the security. If you have a CA then this will not be an issue.

To create a certificate locally, you need the OpenSSL command-line tool.

Change to your Home Assistant configuration directory like ~/.homeassistant. This will make it easier to backup your certificate and the key. Run the command shown below.

The certificate must be .pem extension.

openssl req -sha256 -newkey rsa:4096 -nodes -keyout privkey.pem -x509 -days 730 -out certificate.pem

For details about the parameters, please check the OpenSSL documentation. Provide the requested information during the generation process.

At the end you will have two files called privkey.pem and certificate.pem. The key and the certificate.

Update the http: entry in your configuration.yaml file and let it point to your created files.

http:
  ssl_certificate: /home/your_user/.homeassistant/certificate.pem
  ssl_key: /home/your_user/.homeassistant/privkey.pem

A restart of Home Assistant is required for the changes to take effect.

If you get any log error about ssl_key or ssl_certificate that is not a file for dictionary value when run Home Assistant, you need to change owner or access permission of the .pem files as following:

sudo chown homeassistant:homeassistant certificate.pem privkey.pem
sudo chmod 755 certificate.pem privkey.pem

A tutorial “Working with SSL Certificates, Private Keys and CSRs” could give you some insight about special cases.

iOS and macOS Specific Requirements

iOS

If you are going to use this certificate with the iOS app, you need to ensure you complete all fields during the certificate creation process, then:

  • Send only the certificate.pem file to the iOS device, using airdrop or other transfer method.
  • Open the .pem file on the iOS device, follow the prompts to trust and install it.
  • If you are using iOS 10.3 or newer then additional steps are needed.

iOS 13 and macOS 10.15

There are new security requirements for TLS server certificates in iOS 13 and macOS 10.15. To summarize:

  • The key size must be greater than or equal to 2048 bits.
  • A hash algorithm from the SHA-2 family is required. SHA-1 signed certificates are no longer trusted for TLS.
  • The DNS name of the server must be included in the Subject Alternative Name extension of the certificate.
  • For certificates issued after July 1, 2019:
    • Certificates must contain an ExtendedKeyUsage (EKU) extension containing the id-kp-serverAuth OID.
    • Certificates must have a validity period of 825 days or fewer.