Securing documents with passwords

Add password security

You can limit access to a PDF by setting passwords and by restricting certain features, such as printing and editing. However, you cannot restrict saving copies of a PDF. The copies have the same restrictions as the original PDF. Two types of passwords are available:

Document open password
With a document open password (also known as a user password), users must type in the password you specify to open the PDF.

Permissions password
When you set only a permissions password (also known as a master password), recipients don’t need a password to open the document. However, they must type the permissions password to set or change the restricted features.

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.

All Adobe products enforce the restrictions set by the permissions password. However, if third-party products do not support these settings, document recipients are able to bypass some or all of the restrictions you set.

Important: 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.
  1. Do one of the following:
    • In a single PDF or component PDF in a PDF Portfolio, open the PDF and choose Tools > Protection > Encrypt > Encrypt with Password. (You can also choose File > Properties and select the Security tab.) If you don’t see the Protection panel, see the instructions for adding panels at Task panes.

    • In a PDF Portfolio, open the PDF Portfolio and choose View > Portfolio > Cover Sheet. Then choose Tools > Protection > Encrypt > Encrypt With Password. (You can also choose File > Portfolio Properties and select the Security tab.)

    Note: If these options are unavailable, it’s either because the document or PDF Portfolio already includes security settings, or the PDF was created in LiveCycle Designer ES.
  2. If you receive a prompt, click Yes to change the security.
  3. Select a compatibility level. This option sets the encryption level and key size.

    Encryption algorithm and key size are version specific. Ensure that your encryption level is equal to or lower than the recipients’ version of Acrobat or Reader.

  4. Select the document components to encrypt.

    To allow the document contents to be searched, leave the metadata unencrypted. To create security envelopes, use Encrypt Only File Attachments.

  5. Select the type of password to add, and then type the password in the corresponding field. For each keystroke, the password strength meter evaluates your password and indicates the password strength using color patterns. If you are setting a permissions password, determine the level of access.

    Password strength indicator

  6. To allow recipients to copy PDF content to another document, select Enable Copying Of Text, Images, And Other Content.
  7. Click OK. At the prompt to confirm each password, retype the appropriate password in the box and click OK.

Security options

You can set the following options when you create a PDF or when you apply password protection to a PDF. Options vary depending on the Compatibility setting. Security options are not available for PDF/X standards or presets. The names of the settings may vary in different applications.

Compatibility
Sets the type of encryption for opening a password-protected document. If you choose Acrobat 3.0 And Later (PDF 1.3) option, a low-encryption-level security (40-bit RC4) is used. If you choose Acrobat 5.0 And Later (PDF 1.4) or Acrobat 6.0 And Later (PDF 1.5), a high encryption level (128‑bit RC4) is used. Choosing 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.
Note: Select Acrobat X And Later to apply 256-bit AES encryption to Acrobat 8 and 9 documents.

Be aware that anyone using an earlier version of Acrobat cannot open a PDF document with a higher compatibility setting. For example, if you select the Acrobat X and later option, the document cannot be opened in Acrobat 7 or earlier.

Encrypt All Document Contents (Acrobat)
Select this option to encrypt the document and the document metadata. If this option is selected, search engines cannot access the document metadata.

Encrypt All Document Contents Except Metadata (Acrobat)
Select this option to encrypt the contents of a document but still allow search engines access to the document metadata.

Encrypt Only File Attachments (Acrobat)
Select this option to require a password for opening file attachments. However, users can open the document without a password.

Require A Password To Open The Document
Select this option to require users to type the password you specify to open the document. This option is unavailable if Encrypt Only File Attachments is selected.

Document Open Password
Specify the password that users must type to open the PDF file.
Note: If you forget a password, there is no way to recover it from the document. It’s a good idea to store passwords in a separate secure location in case you forget them.

Restrict Editing And Printing Of The Document
Restricts access to the PDF file’s security settings. If the file is opened in Adobe Acrobat, the user can view the file but must enter the specified Permissions password in order to change the file’s Security and Permissions settings. If the file is opened in Illustrator, Photoshop, or InDesign, the user must enter the Permissions password, since it is not possible to open the file in a view‑only mode.

Change Permissions Password
Specify a password that is required to change the permissions settings. This option is available only if the previous option is selected.

Printing Allowed
Specifies the level of printing that users are allowed for the PDF document.
None
Prevents users from printing the document.

Low Resolution (150 dpi)
Lets users print at no higher than 150‑dpi resolution. Printing may be slower because each page is printed as a bitmap image. This option is available only if the Compatibility option is set to Acrobat 5 (PDF 1.4) or later.

High Resolution
Lets users print at any resolution, directing high-quality vector output to PostScript and other printers that support advanced high-quality printing features.

Changes Allowed
Defines which editing actions are allowed in the PDF document.
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.

Commenting, Filling In Form Fields, And Signing Existing Signature Fields
Lets users add comments and digital signatures, and fill in forms. This option doesn’t allow users to move page objects or create form fields.

Page Layout, Filling In Form Fields, And Signing
Lets users insert, rotate, or delete pages and create bookmarks or thumbnail images, fill out forms, and add digital signatures. This option doesn’t allow them to create form fields. This option is only available for low (40‑bit RC4) encryption.

Any Except Extracting Pages
Lets users edit the document, create and fill in form fields, and add comments and digital signatures.

Enable Copying Of Text, Images, And Other Content
Lets users select and copy the contents of a PDF.

Enable Text Access For Screen Reader Devices For The Visually Impaired
Lets visually impaired users read the document with screen readers, but doesn’t allow users to copy or extract the document’s contents. This option is available only for high (128‑bit RC4 or AES) encryption.

Enable Plaintext Metadata
Encrypts the contents of a document but still allows search engines access to the document metadata.

Remove password security

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.

  1. In the open PDF, do one of the following:
    • Select Tools > Protection > Encrypt > Remove. If you don’t see the Protection panel, see the instructions for adding panels at Task panes.

    • In the Security tab of the Document Properties dialog box, choose No Security from the Security Method menu.

  2. Your options vary depending on the type of password security attached to the document:
    • If the document only had 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.