Composing ask From: address and arbitrary keys in PGP

[GTC at riseup.net]

1. When composing messages, mutt ask To: or recipient adress and Subject: and then go to editor. How to make mutt ask for From: or sender address only and then go to editor?

This is useful for people with multiple accounts or multiple identities in each email account if they set custom headers based on each email account or identity eg, From: address.

2. In PGP, mutt has crypt_opportunistic_encrypt to select keys based on To: address to the recipient. But PGP also need From: address or sender's key to encrypt messages, sign messages or even attch their own public key. By default, mutt uses system default key or oldest key created for encryption, sign messages or attach public key. 

How to choose arbitrary keys from PGP key chain as From: or sender's key to sign, encrypt or attach? Are there also some  "From_crypt_opportunistic_encrypt" based on sende' key?

People with multiple accounts or multiple identities in each email account may want to use different keys that match their corresponding email accounts or From: address to sign, encrypt or attach in corresponding messages.

Ryan