[pim] Re: [MSEC]Re: Q: "open" group multicast se nder authentication...

Attend my Dispatch presentation on an update to TESLA as being used for 
GNSS authentication.

Of course this is a higher layer than multicast and the packets are GNSS 
timestamped so replay protection is there.

There will be a side meeting Wed morning that will also to into the CA 
that the SBAS providers will use to sign the key discloser.  but this is 
a simple CA, as there are very few SBAS providers and very few sats.

EXTREMELY bandwidth and packet size constrained!

ICAO is also looking at this for ADS-B auth where the PKI needs are 
larger.  The PKI in draft-drip-dki would be a good fit for ADS-B and I 
am having a meeting on this at ICAO (a couple blocks over) next week.

I will be updating my draft, draft-moskowitz-tesla-update-gnss-sbas, 
Sunday when submissions is reopened.  I am working on adding the FEC 
process for recovering a lost aMAC to add to what I have ready to submit...

On 10/29/25 7:16 PM, Brian Weis wrote:
> Hi Toerless.
>
> I think you’re remembering the TESLA algorithm, which was documented 
> in RFC 4082.  It needs a key management system to distribute shared 
> keys, but does provide replay attack prevention. There are a couple of 
> other RFCs which describe how TESLA keying material could be used with 
> SRTP, and keys distributed by the MIKEY protocol. You can find them on 
> this page: <https://datatracker.ietf.org/wg/msec/documents/>.
>
> That’s all I know about it though, and I’m not aware if anyone has 
> implemented any of this.
>
> Hope that helps,
> Brian
>
>> On Oct 29, 2025, at 2:49 AM, Toerless Eckert <[email protected]> wrote:
>>
>> Hi folks
>>
>> I am trying to remember if we ever wrote down a mechanism to 
>> cryptograpically
>> authenticate the sender of IP multicast packets - including replay attack
>> prevention! - without having to rely on shared keys like in GDOI and 
>> hence
>> the need to trust a group of receivers.
>>
>> I am pretty sure that there was at some time an interesting 
>> cryptographically
>> new proposal for this - a few years ago - but i don't remember enough 
>> keywords
>> to find it (which WG, what was the name). Even the AI tools are 
>> thoroughly
>> useless ;-))
>>
>> And of course, simple authenticating packets with time-stamps
>> signing with certificate is well-known... and well-known expensive...
>>
>> Cheers
>>    Toerless
>>
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