Acrobat 5 and 6 include both Password and Certificate Security; Acrobat 7 has added the ability to use the Adobe Live Cycle Policy Server. In this chapter you will learn how to work with a range of security methods:

• Password Security is the most familiar method of securing a document. In Acrobat, you can create two levels of passwords for controlling access to both opening and modifying a document.

• Certificate security is based on digital signatures created in Acrobat. In addition to creating certificates, you can also exchange them, set specific rights, and examine their contents.

• Certificate security can be applied in two ways, either as a signature, or as a certifying signature. Both signature options use the same process and encryption method; the difference lies in the order of signing, as only the first signature on a document can be defined as a certifying signature.

• Digital signatures can be customized, using combinations of the signature elements provided, optionally accompanied by a custom graphic image.

• Rather than recreating a set of parameters to apply with a signature or password each time it is used, you can create a policy that is stored in Acrobat and available for use as needed.

• Document attachments can be encrypted separately from the rest of a document using an eEnvelope.

• File versions based on existing content at the time of signing can be compared.