Choosing which type of security to use

Acrobat takes advantage of the security features of Windows XP and a number of other security systems. You can secure a PDF by using the following security methods:
Note: “Security” is sometimes confused with “accessibility,” which involves making documents easier to read for the visually impaired.
Password encryption

Add passwords and set security options to restrict opening, editing, and printing PDFs.



Certification encryption

Encrypt a document so that only a specified set of users has access to it.



Certify a document

Save the PDF as a certified document. Certifying a PDF adds a (visible or invisible) certifying signature that lets the document author restrict changes to the document.



Server-based security policies

Apply server-based security policies to PDFs (for example, using Adobe LiveCycle Policy Server). Server-based security policies are especially useful if you want others to have access to PDFs for a limited time.

Before you secure a PDF, you may want to remove any sensitive or dynamic page content that can compromise the document’s integrity. If others will be filling in, or signing, form fields in the document, you may want to set the form field properties to “read-only” to prevent modifications to the form fields.



If you want to do this:

Do this:

Require a password to open a PDF, or copy or print its contents

Secure the document by choosing Password Encryption from the Secure tasks button.

If your company is signed up, you can also use Adobe LiveCycle Policy Server to secure documents.

Indicate that you approve of the PDF’s content

Sign and certify the PDF. You must obtain a digital ID to add digital signatures.

For Asian languages, you can add an approval stamp.

Prevent forms from being tampered with

Use LiveCycle Designer to secure forms and create locking signature fields. See the Adobe LiveCycle Designer Help.

Send secure file attachments via email

Use security envelopes.

Allow only the people you specify to view a PDF

Encrypt the document. Choose Certificate Encryption from the Secure tasks button, or apply security using the Adobe LiveCycle Policy Server. You must have certificates for those who can view the documents.
If you often apply the same security settings to PDFs, consider creating a security policy to simplify your workflow. Both Adobe LiveCycle Policy Server and certificate encryption let you save settings as a policy. If you apply security settings to large collections of PDFs, you can automate the steps by using the Batch Processing command.
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