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TIP 140: Choosing a Security Method
There are many security functions and activities you can perform in Acrobatanything from adding a password to encrypting a document, as you will see in this chapter. The option you choose depends both on the level of security you need for a document as well as its intended recipients. Most of Acrobat's security policies are controlled through one central dialog, the Managing Security Policies dialog (Figure 140).
Figure 140. You can control most of Acrobat's security features from one dialog.
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What Security Setting Levels Mean
Encryption is a software-based method of controlling who has access to a document. The higher the level of encryption, the greater level of control you have over the document and any actions related to the document. Acrobat uses 128-bit RC4 and 128-bit AES (Advanced Encryption Standard) security methods. You can choose which method to use when securing documents. An encryption algorithm is a method based on the fact that there is no simple way to factor very large numbers. As a result, breaking an encryption key is extremely time consuming and uses a lot of processing power. The differences in security options between Acrobat versions relates primarily to printing and the types of changes users are allowed to make. In earlier versions of the program, specific types of changes were allowed, such as filling in form fields, commenting, and signing. You can also choose various combinations of options and allow specific text access for screen readers used by the visually impaired. |
In Acrobat 7 you can choose the following types of security processes: Password Protection.
Use passwords to prevent unauthorized users from opening documents. You can also specify whether to allow users to copy, print, or extract content from a document. Document Certification.
Certify documents to define the content of a document and show any changes. You can restrict access to a document to specified users using this method. Digital Signatures.
Use Digital Signatures to approve a form or other PDF document. You can also approve a document or form by a number of users all using signatures. eEnvelopes.
Use secure document transmission, called eEnvelopes to protect a document during email distribution. You can also protect attachments using the same type of security.
Checking Security Status
Depending on the security settings applied to a document, you see different icons at the lower left of the program window. Hold your pointer over an icon to see basic information in a tool tip; hold the pointer over the icon for a few seconds or double-click the icon to open a larger dialog with more information. Choose Document > Security > Show Security Settings For This Document or click the Secure task button and choose the command from its menu to open the Document Properties displaying the Security tab. You can choose File > Document Properties > Security to show the Security tab as well. If you want to check the status of a document through a Web browser, choose Document Properties from the arrow icon above the vertical scroll bar on the right side of the document. Then click Security. |
User Security Policies.
Apply security policies to a number of documents at the same time. You can use server systems to add special security features such as controlling access, setting expiry dates, etc.
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