Per Account Settings
Enigmail allows you to specify various options on a per-account basis. This includes the OpenPGP key to be used and the defaults for encrypting and signing messages. These options can be controlled from the menu Tools > Account Settings .... For each account, an OpenPGP Security entry allows you to setup Enigmail.
Enable OpenPGP support (Enigmail) for this identity: if this option is not activated, no encrypted messages can be sent from this identity, and no option can be configured. Note that this does not influence the decryption/verification of received messages, which is independent of any account.
Use Email address of this identity to identify OpenPGP key: if you do not want to specify a key ID, using this option, the key is chosen according to the email address of the account. If you have several keys with the same email address, you should not use this option
Use specific OpenPGP key ID (0x1234ABCD): if this option is selected you can type in the OpenPGP key id you want to use for this account. The key id must be preceeded with 0x (e.g. 0x3FA57EB9). Alternatively, you can click on the Select Key ... button to chose your key from a dialog.
Sign non-encrypted messages by default: if you compose a message from this account, signing is automatically enabled if encryption is not enabled at the same time. You can see the signing status in the lower right corner of the message composing dialog: if the small pencil is green, signing is activated.
Note: If you change the account while composing a message, signing will be activated or deactivated according the chosen account, unless you have modified the signing or encryption status manually!
Sign encrypted messages by default: if you compose a message from this account, signing is automatically enabled if encryption is enabled at the same time.
Encrypt messages by default: enable this option, if you want to automatically try to encrypt messages sent from this account. You can see the encryption status in the lower right corner of the message composing dialog: if the small key is green, encryption is activated.
Note: If you change the account while composing a message, encryption will be activated or deactivated according the chosen account, unless you have modified the signing or encryption option manually!
Always use PGP/MIME: PGP/MIME is a standard defined in RFC 3156 which allows you to encrypt attachments together with the message body and to encrypt HTML mails and special character sets. It is superior to the more common so called inline-PGP standard. Unfortunately, it is only supported by a limited (but growing!) number of mail clients. Apart from Enigmail, currently known are: Apple Mail, Becky, Evolution, KMail, Mulberry, Sylpheed and The Bat!.
If you send messages, they are normally signed and/or encrypted with inline-PGP. Enable this option to use the PGP/MIME standard for all outgoing messages.
Advanced...: open the Enigmail Preferences dialog
Send 'OpenPGP' Header: send a message header information about your key:
- Send OpenPGP key ID: send the key ID specified under "Use specific OpenPGP key ID".
- Send URL for key retrieval: send a URL telling from where your OpenPGP key can be obtained.
Next: Expert Settings