To hook Mailcrypt into Rmail, use the following lines:
(add-hook 'rmail-mode-hook 'mc-install-read-mode) (add-hook 'rmail-summary-mode-hook 'mc-install-read-mode)
Using Emacs version 20.3 or higher, you should use the following lines instead:
(add-hook 'rmail-show-message-hook 'mc-install-read-mode) (add-hook 'rmail-summary-mode-hook 'mc-install-read-mode)