On 19 Apr 2019, at 23:04, Peter <pe...@pajamian.dhs.org> wrote: > But this is just one example of where a header might be signed and then is > later added or altered by the mailing list,
The only headers that mailing lists often alter are subject (though i think that is dying off, hopefully) and the only non-list-mumble header they add generally is sender. Ig you are signing a non-existent sender in a message to a list, that is a mistake. If you are adding a sender header to a message to a list and signing with that header, that is a mistake. Or, you can insist you are right and break list messages. Your call. -- Major Strasser has been shot. Round up the usual suspects.