Dear Mr. Euchner,
This is for your information.
At 17:16 +0200 02/08/23, Euchner Martin ICN M SR 3 wrote:
[...] PL:> You are correct--H.233 does not re-key, but it does have an analogous mechanism to update the initialization vector. H.324 added the codepoint, h233IVResponseTime, to H.245 to express how long the transmitter should wait between transmitting a new IV and transmitting frames based on that IV. This is what I was referring to.
MEU: correct. That's what I found as well. Still, I believe that the time to wait has to be guessed due to some criteria (e.g. network delay etc). So that solution appears to have similar problems as H.235. [...]
In the H.320 system, the encryption control signal and the media to be encrypted are transmitted in the same H.221 framed channel, while in the H.323 system they are transmitted in separate channels (H.245 and RTP). H.233 Initialization Vector is transmitted in one or more blocks of H.221 ECS (Encryption Control Signal) having a 160 msperiod (H.221 multiframe = 10 ms x 16 frames), and takes effect from the start of the next multiframe as described in Section 5.1.3/H.233. The operation is synchronous, thus we need no guess for the time to wait.
Best regards,
OKUBO Sakae e-mail: okubo@giti.waseda.ac.jp ******************************************************************* YRP Office Global Information and Telecommunication Institute (GITI) Waseda University YRP Ichibankan 312 Tel: +81 468 47 5406 3-4 Hikarinooka, Yokosuka-shi, Kanagawa-ken Fax: +81 468 47 5413 239-0847 Japan
GITI Headquarter 29-7 Waseda University Bldg. Tel: +81 3 5286 3831 1-3-10 Nishi-Waseda, Shinjuku-ku, Tokyo Fax: +81 3 5286 3832 169-0051 Japan *******************************************************************
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For help on this mail list, send "HELP ITU-SG16" in a message to listserv@lists.intel.com