emergency-msg — archive

[Art Botterell]

At 10:28 PM -0400 7/14/03, Allen Wyke wrote: >...would the following not be true: > >If a resource is static (ie: you do not want it to change), then the >sender of the CAP message MUST include the resource on a server they >control, and can therefore also control the security of that server - >its "trusted." It's not hard to imagine a scenario under which an issuing agency might want to use a resource served from another agency: e.g., a local emergency management agency might issue a post-earthquake advisory that says something like, "if the ground shaking in your area was strong (areas shown in yellow or red on the USGS shaking-intensity map) then you should inspect your building foundations immediately and check carefully for gas leaks," with the referenced image being a shake map served from a USGS server. And even with a "trusted" server there's always the possibility of accidental (or even malicious) changes occurring on the server after the referencing message is issued. >If the resource is dynamic (ie: you want to point to the latest and >greatest), then all you really can do is point to it. True. Or the sender might not consider the referenced content critical enough to bother with a digest. Which is why the digest would be optional. >That being said, maybe the solution is to put in an attribute that >specifies if the resource is external (not in my network/control) or >internal (default, but can explicitly state it is in my >network/control). Problem is, asserting that the resource is external just raises doubts without providing any way to resolve them. A digest of the asset can be used to determine directly whether the received asset is the same one the sender meant to reference... which is what we really care about... regardless of how or whence it was delivered. - Art