More than four million smart meters and similar devices worldwide are open to cyber attacks due to the security issued in the Open Smart Grid Protocol. The security holes discovered by the researchers allowed them to easily recover private keys without a significant computational effort, an attack they made was composed by just 13 queries to an OMA digest Oracle. The weaknesses in it can be used to determine the private key in a very small number of trials. The experts highlight the importance to be compliant with existing standards, like the DNP3 Secure Authentication that is an IEEE standard.”]
Source: https://securityaffairs.co/wordpress/36648/hacking/flaws-open-smart-grid-protocol.html