Overview	
To PGP Sign or PGP Encrypt a message you open a Message window. There are several ways to accomplish this, all of which start by selecting a Source from which the message will be fetched. Once the selection of the Source is done, you have a choice between:

1. Pressing the Encrypt Sign button in the MacPGP Control window,
2. Choosing the Encrypt-Sign menu item from the File menu,
3. Pressing the Command-E key combination, or
4. Selecting the Encrypt Sign behaviour (see User Interface chapter) and from then on, dragging a text file unto the MacPGP Control application or an alias to it.

Once any one of these actions is performed, a window similar to the following appears on your screen:


 































The window is movable, resizable and zoomable. It is divided horizontally into two sections separated by a 3D-look line:

1. A top part containing push buttons and a popup menu.
2. A bottom part for editing the message itself, specifying the message recipients, attachment files, and various options reagarding the way this message is to be processed.

When you click the zoom box, the Message window expands to the maximum height allowed on your main screen.


Sign or Encrypt	
The top area of the message window contains various push buttons and one popup menu. The Help button, like everywhere else in MacPGP Control will toggle between showing and hiding balloon help text. The popup menu allows you to change the final Destination of the message processing. It is the same as the one found in the MacPGP Control main window. In fact, as soon as you modify this menu, the similar menu in MacPGP Control main window is changed to the same new Destination value.


• Insert… button	
When you press this button you are asked to select a text file. If you do, then the contents of the selected file will replace the current contents of the selection in the Message textbox. If there is no selection active in the Message textbox at the time, then the contents of the selected text file will be inserted where the I-beam cursor is at the time.


• Sign multi-choice button	
Pressing this button is your way of saying you want to Sign only your message. If you intend to do this, there is no need to designate any recipients.

There are three alternatives you can choose from with regard to PGP Signing the message which will appear in a popup menu when you press and hold this button. Your options are:

1. Clear: for clear signing the message,
2. Opaque: for an asciified (ascii armored radix-64) output of the signed message, and
3. Separate: for treating the signature as a separate certificate to be sent to Destination.

This button is only enabled if and when you check the PGP Sign icon checkbox at the bottom of the window.


 

























• Encrypt button	
This button becomes enabled when you have at least one recipient in the Recipients area.

You have two choices for Encrypt: without and with PGP signature. If you checked the PGP Sign icon checkbox at the bottom of the window, then when you press Encrypt, the message will also be PGP Signed before being PGP Encrypted. If the PGP Sign icon checkbox is not checked, then when you press the Encrypt button, the message will only be PGP Encrypted.

Please note that if you specified Eudora as the Destination of your message, and there is one or more Attachment files specified, the Attachments are also treated in the same way the message is. In other words, if you're PGP Signing and PGP Encrypting the message, the attached files will be PGP Signed and PGP Encrypted to the same recipients as well. On the other hand, if you only PGP Sign the message, the attached files will be handed to Eudora as is.

Also, when you press the Encrypt button and the Destination is Eudora, I check first if the Eudora application is running. If it's not I signal that in the Feedback Zone of the MacPGP Control window and return, leaving this message window opened on your screen, thus forcing you to (a) either launch Eudora, or (b) choose a different Destination.


Designating Recipients	
You specify the recipient(s) of the message –if you have to, and you do have to if you're encrypting it– by pressing the button to the left of the Recipients label. When you press this button you will go through the process of selecting recipients as described in Specifying Recipients in the User Interface chapter.


Selecting Attachments	
When the Destination is Eudora, you can also specify attachments to the message. These are files which Eudora will include as MIME parts to the message. To designate attachments you can (a) drag and drop the file's icon from your desktop to the Attachments listbox, and/or (b) push the button to the left of the Attachments label.

When you press the Attachments button, a dialog similar to this one is displayed:


 













• Add… button	
Press this button to select, through a standard Finder choose file dialog, the file you want attached.


• Trash icon button	
This icon-button will become enabled when there is at least one file selected in the Attachments listbox. Press this button to delete the selected entry from the list. Alternatively you can drag the file entry unto the Trash icon and it will be deleted. Finally, double-clicking an entry in the Attachments listbox will also delete it.


• Microphone icon button	
Press this icon to instruct MacPGP Control to start a voice recording session and include the result file as an attachment to the list. Details on how to do that are given in •• Source = Microphone in the User Inteface chapter.


Note
If you specified Eudora as the Destination of your message, and there is one or more Attachment file specified, the Attachments are also treated in the same way the message is. In other words, if you're PGP Signing and PGP Encrypting the message, the attached files will be PGP Signed and PGP Encrypted to the same recipients as well. On the other hand, if you only PGP Sign the message, the attached files will be handed to Eudora as is.


In addition to the resizability of the Message window, and in case your screen is too small to take advantage of this feature, I added this 2-state icon (the blue arrow just to the right of the window below the 3D-look line). By default it points down, but when you press it, it hides the Recipients and Attachments listboxes and lengthens the height of the Message textbox, thus giving you more room.


 






















Editing the message	
The message editing area is the middle part of the window. It displays the message as brought from the Source in a mono-spaced font (Monaco 10pt.). During the execution of the requested action –be it Encryption or Signing– this area will show the current contents of the text.  For example, if you choose to Encrypt after wrapping your message to say 64 columns, the Message area will display the wrapped text, then the ciphered text before the dialog is dismissed, etc…

 










When the Destination is not Eudora, and you checked the Word Wrap icon checkbox, a blue 80-column Ruler becomes visible at the top of this area to give, in combination with the red Width Slider and the Message area width a visual feedback on the message's final look.

When Wrap Message is checked, the Message area is resized and the maximum number of characters per line is indicated in the non-editable Max. Line Length textbox just to the right of the Wrap Message icon checkbox.

To change the maximum line length for wrapped messages, click on the red Width SLider in the ruler area and drag to position. The message window width will then change to reflect the new line length and the value will be shown next to the Wrap Message icon.


 




















You can edit the text of your message directly from the keyboard. The only restrictions are (a)  you can not enter Tab characters in the message, and (b) the total contents of the Message Area should not exceed 32K. If after tabbing out of the Message area, MacPGP Control finds that there are more than 32000 characters there, the Overflow Indicator will turn Red. It will switch back to Green, if at any time the count comes down to below the 32000 characters mark.


Note: When you uncheck the Wrap Message icon, meaning that you don't want your message to be word-wrapped, the un-wrapped message will be displayed in the message window which will expand to show you the first 80 characters only of each line/paragraph. If you still want to edit your message and treat it as un-wrapped, you have to (a) tell MPGPC that you want to wrap the message, (b) edit the message contents, and (3) uncheck the Wrap Message icon. Remember not to enter any Carriage-Return characters while doing this, since MPGPC then considers the <CR> to be an indiaction of a start of a paragraph.


Checking the Options	
The bottom part of the message window contains global indicators that affect the way your message is gonna be treated. Some of them if unchecked, will disable certain buttons in the window —such as the PGP Sign button.


 









I use similar icons to those of Eudora (with permission), to minimize confusion and also because they imply the same actions and concepts.


• Expand Tabs	
One main reason for getting Bad Signature Warning from [Mac]PGP, besides the obvious eventuality that the message has been tampered with, is the difference in treatement of special characters such as Tab between [Mac]PGP, email applications and Internet transports. Eudora for example allows replacement of Tabs by a number of spaces (8 in 1.5.1). If you were preparing your message in an Editor such as BBEdit, you can also set in the preferences the number of spaces for Tab replacement. Because MacPGP when building the hash code, counts the Tab as a single character, this difference in the total count of characters in the message will cause a Bad Signature Warning on the receiving end.

Although Eudora has the possibility of turning off this option, and hence make MacPGP and Eudora on your end of the communication channel agree on the total number of characters in the message, keeping any Tab characters might still be a cause of confusion for the receiving software.

To prevent Tabs and their arbitrary expansion into spaces, you can eliminate totally Tabs from your message and ask MPGPC to do the expansion before Clear Signing the message and sending it to Eudora (or elsewhere for that matter). You specify the number of spaces to replace a Tab in the popup menu next to this icon/checkbox.


• Transliterate	
Another reason that can cause disagreement between the encrypting and decrypting ends are the use of non USASCII 7-bit characters. SMTP, the mail protocol for mail delivery systems on the Internet, can only handle 7-bit character codes. All you hear and read about MIME and Quoted Printable protocoles are attempts used to allow in-transit translation of 8-bit (or more) characters into 7-bit ones.

Again this is no sure way for guaranteeing that your message will not be massacered by some mail forwarder system. The only way to ensure that your mail message will be transmitted as such is to limit it to 7-bit USASCII code.

While waiting for MacPGP to handle this sort of issue, MPGPC offers you the possibility of transliterating your message into a 7-bit character stream. You have the choice of using one of two transliteration tables: a 1-to-1 or a 1-to-many. Which table to use can be specified using the popup menu next to this icon/checkbox. The popup menu is only enabled when you check the icon.

See Transliteration Table… menu item under the Edit menu in the Application Menus chapter for more details about such tables.


• Wrap Message	
As the name implies, checking this option will force a word wrap of the message to the specified limit before processing it through MacPGP. The limit or maximum line length is indicated by the red Width Slider and message editing window width discussed in the section: Editing the message. You can choose values in the range between 20 and 80 inclusive by gliding the red arrow in the ruler area to a new position. If you try dragging the slider to the left of the 20th column, as soon as you release your pointing device, the slider will move to the 20th position, indicating that this is the minimum allowed.

When checked (inverted as in the picture above), your message will be word wrapped to a maximum line length value indicated in the Max. Line Length field —the non-editable field to the right of this icon/checkbox.


When you specify Eudora as the Destination of the message, this icon/checkbox becomes disabled, the Ruler and the Width Slider become invisible, and the message editing window becomes 80-character wide showing your text in wrapped mode. In this case (Destination = Eudora), you don't have to worry about word-wrapping and the maximum line length. This information is collected by MPGPC from Eudora itself if it is running at the time when delivering the message.


• Include Clear Signature	
Check this icon to indicate that you want to include your e-mail signature at the bottom of the message text. The signature will be taken from the Internet Config Preferences file, if such file can be found.


• PGP Sign	
This is your way to tell me if you want to PGP Sign the message and what User ID to use. The popup User IDs to the right of this icon checkbox becomes enabled and will contain the list of all your User IDs found in your secret keyring at the time the window was first invoked. The default selected one is the User ID found at the top of the secret keyring file.

Note: The values in the User IDs popup menu includes all your User IDs found in your secret keyring file. The name and location of this file are read from the PGP Preferences file updated by MacPGP.