addresses

From: Jøran Øygårdvær <jøran@example.com>
Cc: Jøran Øygårdvær <jøran@example.com>
Signed-Off-By: Jøran Øygårdvær <jøran@example.com>
To: Arnt Gulbrandsen <arnt@example.com>
Date: Thu, 20 May 2004 14:28:51 +0200

The From and Cc fields contain addresses. Signed-Off-By may appear to
contain an address, but syntactically that's just a string.

An EAI downgrader should either remove the Signed-Off-By or apply
quoted-printable encoding. There are arguments in favour of both
courses of action.

Removing: Maybe it's syntax? Maybe it's a signature? Removing
Signed-Off-By will at least prevent the end-user's software from
seeing an invalid signature or crash on a syntactically invalid header
field.

Applying quoted-printable: There at least a hope that a human looking
at the message will be able to guess what happened and recover whatever
information was in signed-off-by.