On Mon, Sep 13, 2010 at 11:01 AM, [email protected] <[email protected]> wrote: > > The 50,000 ft view is that IPsec HMAC-SHA1 > costs about the same amount of processing as TCP. ... > Even with the heaviest > authentication (HMAC-SHA1) the video was completely intelligible with > only the occasional stutter.
Also, even if you did have a setting where the CPU cost of HMAC-SHA1 was a significant part of your performance (at e.g. 12 cycles per byte [1]), then you could always switch to Poly1305 or VMAC (at e.g. 2 cycles per byte), or to an authenticated encryption mode (effectively zero cycles per byte?). So while the trade-off of giving up a little security in order to achieve even lower CPU costs is theoretically interesting, in practical terms you can get full security at a negligible CPU cost. (The cost of including the MAC tag bytes in each packet is a different matter.) Regards, Zooko [1] http://cryptopp.com/benchmarks.html _______________________________________________ cryptography mailing list [email protected] http://lists.randombit.net/mailman/listinfo/cryptography
