Today I saw notaries asking about encryption on two notary forums. First I saw this request from Cheryl Elliot about document encryption for documents to be sent to title companies or the like. Then I saw a more general question from Linda Kauffman about encryption for notaries.
So what are some general requirements that notaries would look for in encryption software? The first question is whether the files are to be encrypted on the notary's PC in case the PC gets stolen or if they are to be sent to other people in encrypted form. I don't have enough knowledge to write about the first question, I'll only write about encrypting files to be sent to others.
So lets look at potential recipients. Some may be home users on a tight budget. They won't buy anything just for encryption, and they won't buy software that costs hundreds of dollars (or $XX per month for a subscription). So they will have Adobe Reader, but they won't have Microsoft Office or Adobe Acrobat. They might be unwilling to download software from an unfamiliar source, or might not be competent to do so.
Other potential recipients will be using computers issued by their employers, which are good-sized corporations or government agencies. They'll probably have Microsoft Office (although possibly an old version) and Adobe Reader, but maybe not Adobe Acrobat. They won't be allowed to download and install any software.
As a group, potential recipients will use a variety of email solutions, and will not be willing to establish a new email account just because this special email account supports the encryption favored by the notary. So email encryption is a non-starter; it will be necessary to encrypt the document separately and send it as an attachment to an email.
The only common software mentioned in all of the above is Adobe Reader. Adobe Reader supports both password protection and public key cryptography (also called public key infrastructure [PKI], digital certificates, or X.509). But setting up public key cryptography is a complex business, so I'll only consider password protection. The notary can do this by subscribing to Adobe Acrobat. The password-protected files produced by Acrobat can be read by the free Adobe Reader that virtually everyone has.
The notary can save money by downloading and installing the free PrimoPDF. This supports the creation of password-protected PDFs. It is similar to various print-to-pdf functions out there, and causes some subtle changes to the images, such as dots-per-inch changes, so may not be suitable for some files.
The process of sending password-protected PDFs is essentially a one-way solution. If the recipient wants to send an encrypted reply, but doesn't have Adobe Acrobat, and isn't allowed to install PrimoPDF, the recipient won't have any way to send the encrypted reply.