Extracting Blocks of Text from PDF

Before you can copy sections of text in a PDF document to the Clipboard or another open document, you need to select the text in the PDF document. To select text in a PDF document, you use two of the three different tools found on the Selection toolbar, which is attached to the Basic toolbar:

• Select Text tool (V): Use this tool to select lines or columns of text by dragging through them.
• Select Table tool (Shift+V): Use this tool to select a table or block of text with its formatting by drawing a bounding box around the table or text block.

You can also use the TouchUp Text tool (press T to select this tool) to select a block of text defined by its underlying document structure tags, such as whole headings or whole paragraphs. True to its name, this tool should be used only when you need to extract small amounts of text from a PDF document. Like the text selection tools on the Basic toolbar, text selected with the TouchUp Text tool can be copied, deleted, edited, and placed in other program documents . When you use the Select Text tool to select lines or columns of text in a PDF document, you can then copy the selected text to the Clipboard by choosing Edit➪Copy or by pressing Ctrl+C (Ô+C on the Mac). After you’ve copied the text to the Clipboard, you can switch to a document open in another program and then paste the copied text into the file by using that program’s Edit➪Paste command or by pressing Ctrl+V (Ô+V on the Mac).

Encrypting PDF Files

The last and most secure type of security that you can add to your PDF documents employs the Certificate Security system that you use to digitally sign documents, along with the list of Trusted Certificates in your user Digital ID file. When you encrypt a PDF document with Certificate Security, no one has access to the document other than those you specifically designate as recipients, and you can designate as recipients only those persons who are already on your Trusted Certificates list.
The steps for encrypting a PDF document with Certificate Security are as follows:

1. Choose Document➪Security➪Encrypt for Certain Identities Using Certificates. The Restrict Opening and Editing to Certain Identities dialog box opens.
2. In the Identity Directories list box, click the name of the person you want to add to the Recipients list box below, and then click the Add to Recipient List button.
3. Click the name of the newly added recipient to highlight it in the Recipients list box.
4. Click the Set Recipient Permissions button. By default, Acrobat grants the recipient full access to the PDF document whose user permissions include general editing, commenting and form field authoring privileges, the ability to print the document at any print resolution, and full copying and extraction privileges.
5. To restrict the recipient’s user permissions in some way, click the Restrict Printing and Editing of the Document and Its Security Settings button.
6. Limit the permissions by deselecting the Enable Text Access for Screen Reader Devices for the Visually Impaired check box and/or the Enable Copying of Text, Images and Other Content check box and/or by selecting new options in the Changes Allowed and Printing Allowed drop-down lists before you click OK.
7. Repeat Steps 3 through 6 (as they apply) to add your other recipients from the Identity Directories list box and set their user permissions in the Recipients list box.
8. After you’ve added all the recipients and set their user permissions, click the OK button. If the Certificate Security - Alert box appears, telling you that settings will not be applied until you save your PDF document, click OK. You can also opt to not show this dialog box in the future by selecting the Do Not Show This Message Again check box before you click OK.
9. Choose File➪Save to save the Certificate Security encryption settings for the current document. Alternatively, choose File➪Save As and edit the filename and/or folder location of the encrypted document before clicking the Save button. After you save your PDF file encrypted with Certificate Security, you can distribute copies to all the people you added to the Recipients list. When someone on the list tries to open the encrypted file, Acrobat displays the Select My Digital ID File dialog box, where the user selects his or her user Digital ID and enters his or her user password. When the user clicks the OK button to close the Select My Digital ID file dialog box, Acrobat checks the user’s public key against the certificate information (specifically the MD5 and SHA-1 fingerprints) in the encrypted file.

When Acrobat finds they match, it then opens the PDF document. The user then has access to the opened document according to user permissions that you set. To check these permissions, the user can right-click (Control+click on the Mac) the Document Encrypted key that now appears on the Document pane Status bar (a locked padlock on the left of the Status bar), select Document Security on the context menu, and then click the Security Settings button in the Document Properties dialog box.
If someone not on the Recipients list attempts to open a PDF document that’s encrypted with Certificate Security, upon logging in, he or she will receive the Certificate Security - Alert dialog box with the message You do not have access rights to this encrypted document. When the user clicks OK to clear this dialog box, the document will fail to open.

Comparing signed PDF documents

Each time a person digitally signs a PDF document that already has one signature, Acrobat saves the changes and signature of each subsequent signatory in a special appended version of the file. You can then compare the various versions to note what changes, if any, each signatory made.
Acrobat notes when a PDF document that you’ve sent out for subsequent signatures comes back to you with changes by adding a Document Was Modified item to the Signatures palette. You can then display the details of the modifications by clicking the Expand button (with the plus sign on Windows and the triangle pointing to the right on the Mac). Note that the detailed change items shown in the expanded list are purely informational and do not perform as bookmarks.
To have Acrobat do a side-by-side comparison of the versions to let you visually compare the changes, select View Signed Version on the Signatures palette Options pop-up menu. Acrobat then displays the original version of the PDF file and the most current version in a Document pane. To compare the files side by side, choose Window➪Tile➪Vertically. You can then scroll through the pages, visually noting the differences. When you’re finished checking the changes, close the original version on the left by clicking its document window’s Close button and maximize the latest version on the right by clicking its document window’s Maximize button. If you would prefer, you can have Acrobat do a page-by-page comparison and locate all the changes between the latest signed version and the original. To do this, select Compare Signed Version to Current Document on the Signatures palette Options pop-up menu. Acrobat then performs a page-by-page comparison and creates a second PDF document containing only the pages that have changed. These changed pages are displayed side by side. When you have finished comparing these pages, you can close this newly created document by pressing Ctrl+W (Ô+W). You can then save it in its own PDF file by clicking the Yes button in the alert dialog box that asks you if you want to save the changes before closing. If you have no further need for this comparison PDF file, you can click the No button to abandon the comparison document and just return to the most up-to-date signed version of the PDF document.