Using X.509 certificates to authenticate devices to IoT hub

Question

Hello ,

I am using X.509 certificates to authenticate devices to IoT hub using a MQTT client as shown in the code snippet below:

TrustRootCER = "./DigiCertGlobalRootG2.crt"

deviceCert = "./18B8C0FC73A9F382CE48FDAAB5A46E14.pem"

deviceCertKey = "./device1.key"

client.tls_set(ca_certs=TrustRootCER, certfile=deviceCert, keyfile=deviceCertKey, cert_reqs=ssl.CERT_REQUIRED, tls_version=ssl.PROTOCOL_TLSv1_2, ciphers=None)

The client fails to connect with error below:

 context.load_verify_locations(ca_certs)

ssl.SSLError: [X509: NO_CERTIFICATE_OR_CRL_FOUND] no certificate or crl found (_ssl.c:4154)

Could you let me know if I am using the right certificate DigiCert Global Root G2 or if I am missing anything over here.

Thanks

Answer 1

Hello @Arun Kumar,

welcome to this moderated Azure community forum.

The Azure IoT Hub uses a Digicert certificate to encrypt the transport of data (TLS).

You can which certificate is used using:

openssl s_client -connect [your iot hub].azure-devices.net:8883

For example, I check my personal IoT Hub:

As you can see, the Digicert G2 is used.

You can find the public cert file here. Please verify you have a legit certificate (don't just copy them directly from the internet :-) ).

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