The
message-cancel-news command cancels the article in
the current buffer.
The value of
message-cancel-message is inserted in the body of
the cancel message. The default is ‘I am canceling my own article.’.
When Message posts
news messages, it inserts Cancel-Lock headers by
default. This is a cryptographic header that ensures that only
you can cancel your own messages, which is nice. The downside is
that if you lose your .emacs file (which is where Gnus stores the
secret cancel lock password (which is generated automatically the
first time you use this feature)), you won't be able to cancel
your message. If you want to manage a password yourself, you can
put something like the following in your ~/.gnus.el file:
(setq canlock-password "geheimnis"
canlock-password-for-verify canlock-password)
Whether to insert the header or not is controlled by the
message-insert-canlock variable.
Not many news servers respect the Cancel-Lock
header yet, but this is expected to change in the future.