mml-sign-alist

mml-sign-alist is a variable defined in `mml-sec.el'.
Its value is

(("smime" mml-smime-sign-buffer mml-smime-sign-query)
 ("pgp" mml-pgp-sign-buffer list)
 ("pgpauto" mml-pgpauto-sign-buffer list)
 ("pgpmime" mml-pgpmime-sign-buffer list))

Documentation:
Alist of MIME signer functions.