On Tue, Mar 8, 2011 at 3:55 PM, Peter Gutmann <[email protected]> wrote: > > Martin Rex <[email protected]> writes: > >>Truncating HMACs and PRFs may have become first popular in the IETF within >>IPSEC. > > It wasn't any "may have become first popular", there was only room for 96 bits > of MAC data in the IP packet, so MD5 was truncated to that size.
This is an odd claim, since: (a) RFC 1828 (http://tools.ietf.org/html/rfc1828) originally specified not HMAC but a keyed MD5 variant with a 128-bit output. (b) The document that Martin points to has MACs > 96 bits long. Can you please point to where in IP there is a limit that requires a MAC no greater than 96 bits. -Ekr _______________________________________________ Ietf mailing list [email protected] https://www.ietf.org/mailman/listinfo/ietf
