Hi Mike,
the signature size of RSA is an issue even in the 1024 bit version. The main wireless protocol, 802.15.4 has a PHY/MAC packet size of 127 bytes so we will have to fragment IP packets (Bluetooth LE is even smaller at just 27 bytes). This makes it very difficult to meet the time to light requirements. This is also a concern for the 70-80 byte overhead of ECC but we can probably just about manage. Abhinav ________________________________ From: Ace <ace-boun...@ietf.org> on behalf of Michael StJohns <mstjo...@comcast.net> Sent: Wednesday, February 8, 2017 3:55:22 AM To: ace@ietf.org Subject: [Ace] Asymmetric signature performance Hi - This is sort of non-obvious, but one or two articles I read suggest that RSA 1024 performance may be better than the ECDSA equivalent. The tradeoff here is obviously the size of the signature and the transmission thereof, but... While 1024 bits isn't an ideal security strength for RSA, using any asymmetric key system for source authentication in group systems is going to be much better than trying to pretend that symmetric group key systems have any authentication properties at all. I saw a PPT presentation by Hannes that didn't include any RSA performance numbers for the ARM processors even though the key sizes were compared. My guess is that someone has numbers for 1024 RSA signatures on the tiny ARM processors that might be useful to throw into the mix. https://www.cryptopp.com/benchmarks.html has comparison values for a specific library. What I'm suggesting is that we figure out how to meet the "can't cost anything" requirement with weaker asymmetric keys rather than accepting a low end fantasy of symmetric key multicast authentication. Mike _______________________________________________ Ace mailing list Ace@ietf.org https://www.ietf.org/mailman/listinfo/ace ________________________________________________________ The contents of this e-mail and any attachments are confidential to the intended recipient. They may not be disclosed to or used by or copied in any way by anyone other than the intended recipient. If this e-mail is received in error, please immediately notify the sender and delete the e-mail and attached documents. Please note that neither the sender nor the sender's company accept any responsibility for viruses and it is your responsibility to scan or otherwise check this e-mail and any attachments.
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