Subject: Re: [Dtls-iot] Fwd: [dice] #4 (profile): Random Number Generation

From: Michael StJohns <[email-masked]>
Date: Thu, 17 Jul 2014 13:38:46 -0400

On 6/21/2014 2:19 PM, Hannes Tschofenig wrote:
>   Recommendation: IoT devices using TLS must use a hardware-based random
>   number generator since the typical sources contributing to the randomness
>   pool are not available on an embedded device (such as mouse movement,
>   keyboard input, etc.).

I've started to go through Hannes' recommendations.  I'm going to 
address the ones where I have some issues first.

I disagree with the above recommendation being part of TLS or DICE as 
its attempting to impose an implementation requirement.  Instead, let's 
do this as a recommendation about requirements for random number 
quality, and minimum required entropy.

In the IOT case, seeding a good PRBG from a source of RF noise may be an 
acceptable approach for example if there is sufficient entropy in the 
available noise and that's usually congruent to whatever the required 
security strength is for the application.

E.g. instead:

IoT devices must have a source of entropy able to produce N bits of 
entropy input prior to the first use of the random number generator.  
The random number generator must be considered secure for use with 
algorithms of N bits of security.