Thanks Hannes. Before I try to address it, can you help me understand what you are proposing. To amend this paragraph maybe?
-----Original Message----- From: Ace <[email protected]> On Behalf Of Hannes Tschofenig Sent: Thursday, May 09, 2019 10:43 AM To: [email protected] Subject: [Ace] EST over CoAP: Randomness Hi all, I am still a bit unhappy about this paragraph: " Constrained devices sometimes do not have the necessary hardware to generate statistically random numbers for private keys and DTLS ephemeral keys. Past experience has also shown that low-resource endpoints sometimes generate numbers which could allow someone to decrypt the communication or guess the private key and impersonate as the device [PsQs] [RSAorig]. Additionally, random number key generation is costly, thus energy draining. " If you get hardware that does not have a hardware-based RNG then you are in trouble. The main security protocols we look into do not work without a source of randomness. Hence, getting the certificate & private key from the server will not get you too far. I believe we should encourage developers to pick the correct hardware for the task rather than making them believe we have come up with solutions that allow them to get away without a hardware-based RNG. I also do not believe the statement that random number key generation is costly. Can you give me some number? The references to [PsQs] [RSAorig] are IMHO also not appropriate because they are conveying a different message (at least that's my understanding from reading them). The message is that you have to be careful with designing and using a random number generator on embedded systems because the sources of entropy may just not be there (like keyboards, harddisk drive, processing scheduling, etc.). Ciao Hannes IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. _______________________________________________ Ace mailing list [email protected] https://www.ietf.org/mailman/listinfo/ace _______________________________________________ Ace mailing list [email protected] https://www.ietf.org/mailman/listinfo/ace
