VM is a Mail User Agent for Emacs

To start VM:

M-x       vm  

Mail Keys:

m    compose new message  

r     reply to message, do not include text  

R     reply, and include text  

z     forward message  

f     reply to all recipients, do not include text  

F     reply to all, include text  

g     get new mail  

C-c  C-a      attach file  

C-c  C-i      insert file in message  

C-c  C-c    mail the message, exit  

C-c  C-s      mail the message, stay in buffer  

C-c  C-w      insert signature from ~/.signature  

M-x  ispell-message       spell check message  

C-c  C-f C-c      create cc header  

C-x  k     kill buffer    

n     move to next message  

p     move to previous message  

>     go to last message  

<     go to first message  

d     delete message  

#     remove all deleted messages  

u     undelete  

t     toggle hidden headers  

q     quit VM  

Configuration:

Place vm.elc in ~/emacs file, with line in ~/.emacs to load this file:

(load "~/emacs/vm")

Custom VM config should be placed in ~/.vm

Mailcrypt:

Mailcrypt can be used to sign and encrypt messages using gpg:

C-c  /  s         sign

C-c  /  e     encrypt (will prompt for sign)

C-c  /  d     decrypt
 

C-c /  x     insert public key

C-c /  k     fetch public key

Configuration:

To set gpg as default add to ~/.emacs:

(mc-setversion "gpg")

If you have more than one key, specify the one to use:

(setq mc-gpg-user-id "User Name")

To add a personal comment:

(setq mc-gpg-comment "mailcrypt 3.5.5")

Changing Default ID:

To change the default ID, edit the file vm-misc.el (or vm-misc.elc if byte-compiled) in:
1) /usr/share/emacs/19.34/site-lisp/vm/
2) /usr/share/emacs/20.7/site-lisp/vm/

changing the item in quotes (devnull.org in this example).
mail-host-address)
   (t "devnull.org")))