[EAS] This weeks IPAWS RWT

[Ed Czarnecki]

I messed up my own typing there - the hazards of being on both a Skype and a phone call simultaneously, while typing emails.  

100% of *complaint EAS devices will not let an invalid alert forward, they will just log the receipt.  Our systems, for example, just log an invalid signature, the logs will say "Decoded alert 'RWT' will not auto-forward" and the web interface will say "Log: Digital Signature --> Invalid, Rejected."

Other systems may reject a message with an invalid digital signature, but not provide the user with any flag that an invalid message was not received.

The bottom line for compliance purposes is that a message with an invalid digital signature does not move to forwarding (transmission).  Manufacturers may signal the user differently about invalid messages (or not at all).

From: EAS <eas-bounces at radiolists.net> on behalf of KALX Engineering <engineering at kalx.berkeley.edu>
 
Hmmm, 100%?  My EASyCAP B3030 is set to check for a valid digital signature and I did receive and log this week's RWT.  Is my unit not compliant?

-Greg

On Mon, Apr 26, 2021 at 10:48 AM Ed Czarnecki <ed.czarnecki at digitalalertsystems.com> wrote:
>Um, well that should mean that 100% of *compliant EAS devices will not log the receipt.  Section 11.56 of the FCC's rules requires EAS Participants to "configure their systems to reject all CAP-formatted EAS messages that include an invalid digital signature."  In other words, 11.56(c) basically **requires EAS devices to check digital signatures.

>Maybe this is a useful exercise in a different way.  If the below is correct , and if your EAS device IS logging the RWT in question, then it might be a very good idea to double check that digital signature validation is actually enabled on your EAS device.

>If it is not enabled, then you should enable digital signature verification.

>If you're EAS device does not allow digital signature verification ... you'd better contact your respective vendor ...

--
Greg German
Chief Station Engineer
KALX 90.7FM
26 Social Sciences Bldg, Berkeley, CA 94720-5650
Ph: 510.847.2148
https://www.kalx.berkeley.edu

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