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Note:
This document provides instructions for Acrobat DC and Acrobat 2017. If you're using Acrobat XI, see Acrobat XI Help.
You can limit access to a PDF by setting passwords and by restricting certain features, such as printing and editing. However, you cannot prevent saving copies of a PDF. The copies have the same restrictions as the original PDF. Two types of passwords are available:
Document open password
A Document Open password (also known as a user password) requires a user to type a password to open the PDF.
Permissions password
A permissions password (also known as a master password) requires a password to change permission settings. Using a permissions password, you can restrict printing, editing, and copying content in the PDF. Recipients don’t need a password to open the document in Reader or Acrobat. They do need a password to change the restrictions you've set.
If the PDF is secured with both types of passwords, it can be opened with either password. However, only the permissions password allows the user to change the restricted features. Because of the added security, setting both types of passwords is often beneficial.
Note:
You cannot add passwords to a signed or certified document.
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Select an Acrobat version from the Compatibility drop-down menu. Choose a version equal to or lower than the recipients’ version of Acrobat or Reader.
Options control compatibility with previous versions and type of encryptionThe Compatibility option you choose determines the type of encryption used. It is important to choose a version compatible with the recipient's version of Acrobat or Reader. For example, Acrobat 7 cannot open a PDF encrypted for Acrobat X and later.
- Acrobat 6.0 And Later (PDF 1.5) encrypts the document using 128-bit RC4.
- Acrobat 7.0 And Later (PDF 1.6) encrypts the document using the AES encryption algorithm with a 128-bit key size.
- Acrobat X And Later (PDF 1.7) encrypts the document using 256-bit AES. To apply 256-bit AES encryption to documents created in Acrobat 8 and 9, select Acrobat X And Later.
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Encrypt All Document Contents
Encrypts the document and the document metadata. If this option is selected, search engines cannot access the document metadata.
Encrypt All Document Contents Except Metadata
Encrypts the contents of a document but still allows search engines access to the document metadata.
Note:
The iFilter and the Find or Advance Search commands of Acrobat do not look into the PDF’s metadata even when you select the Encrypt All Document Contents Except Metadata option. You can use a search tool that takes advantage of XMP metadata.
You can prevent users from changing PDFs. The restrict editing option prohibits users from editing text, moving objects, or adding form fields. Users can still fill in form fields, sign, or add comments.
You can prevent users from printing, editing, or copying content in a PDF. You can set the restrictions you want to apply to the PDF. Users cannot change these restrictions unless you give them password.
Illustrator, Photoshop, or InDesign do not have view‑only modes. To open a restricted PDF in these applications, the user must enter the permissions password.
Note:
If you forget a password, you cannot recover it from the PDF. Consider keeping a backup copy of the PDF that isn’t password-protected.
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None
Prevents users from making any changes to the document that are listed in the Changes Allowed menu, such as filling in form fields and adding comments.
Inserting, Deleting, And Rotating Pages
Lets users insert, delete, and rotate pages, and create bookmarks and thumbnails. This option is only available for high (128‑bit RC4 or AES) encryption.
Filling In Form Fields And Signing Existing Signature Fields
Lets users fill in forms and add digital signatures. This option doesn’t allow them to add comments or create form fields. This option is only available for high (128‑bit RC4 or AES) encryption.
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Select an Acrobat version from the Compatibility menu. Choose a version equal to or lower than the recipients’ version of Acrobat or Reader. The Compatibility option you choose determines the type of encryption used. It is important to choose a version compatible with the recipient's version of Acrobat or Reader. For example, Acrobat 7 cannot open a PDF encrypted for Acrobat X and later.
- Acrobat 6.0 And Later (PDF 1.5) encrypts the document using 128-bit RC4.
- Acrobat 7.0 And Later (PDF 1.6) encrypts the document using the AES encryption algorithm with a 128-bit key size.
- Acrobat X And Later (PDF 1.7) encrypts the document using 256-bit AES. To apply 256-bit AES encryption to documents created in Acrobat 8 and 9, select Acrobat X And Later.
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Encrypt All Document Contents
Encrypts the document and the document metadata. If this option is selected, search engines cannot access the document metadata.
Encrypt All Document Contents Except Metadata
Encrypts the contents of a document but still allows search engines access to the document metadata.
Note:
The iFilter and the Find or Advance Search commands of Acrobat do not look into the PDF’s metadata even when you select the Encrypt All Document Contents Except Metadata option. You can use a search tool that takes advantage of XMP metadata.
You can remove security from an open PDF if you have the permissions to do so. If the PDF is secured with a server-based security policy, only the policy author or a server administrator can change it.
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Your options vary depending on the type of password security attached to the document:
- If the document had only a Document Open password, click OK to remove it from the document.
- If the document had a permissions password, type it in the Enter Password box, and then click OK. Click OK again to confirm the action.
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