In addition to well-known protection methods such as firewalls, virus scanning and anti-spy software, the program offers a comprehensive system for securing your PDF documents at different protection levels:

• Apply a password security scheme to your PDF document so that it requires a password for opening and/or a further password to set or change a series of permitted and prohibited actions.

• Apply a certificate security scheme to your document to encrypt it with a Public Key you have received from a trusted contact, so that it can only be decrypted by that contact or by partners having the corresponding Private Key, as described in Sharing Security Certificates.

• Use digital signatures for your PDF document that can specify which actions are allowed. Even for a document with no security settings, at least a warning is given if changes have been made to it since it was signed. Verify a digital signature on an incoming PDF document to make sure it was sent by a trusted contact.

• Perform redaction and document element removal to create a publicly viewable version from documents with sensitive content.

• Prepare an e-mail package for secure delivery: select an envelope page, one or more attached PDF documents, a certain encryption method applied to the package, and a digital signature.

See also Security Preferences and Security Panel. Password and Certificate security use encryption for document content, signatures and certified documents protect the signature and its associated data by encryption. For detail on available encryption levels, see About PDF versions.