Free alternative to Digify or Locklizard

What is Adobe Content Server?
Adobe Content Server is a server controlled approach to Digital Rights Management (DRM) that was introduced by Adobe for PDF documents (DRM PDF). It's a system to protect digital books in PDF, EPUB, and EPUB3 formats. Adobe Content Server was developed to provide an extension to the early DRM controls that Adobe provided within their PDF product. These were to control user access (by use of a password), prevent editing (also exporting, but not necessarily copying) and reduce printing quality. As Adobe noted, not all PDF viewers actually ‘respected’ the controls offered, so there were methods for bypassing the initial control system. Adobe Content Server DRM controls could be applied to PDF documents, and also to documents using the ePub format Adobe digital editions, and was respected on a number of platforms capable of processing those formats. The Adobe Content Server licensing model was based upon a joining fee, an annual maintenance fee and a charge per protected document delivered to an end user/customer.

The problem with adobe content server is obvious, it's expensive, and not even interested in personal use. And if the reader do not agree to install certain software to view the DRM file, then the files is a digital rubbish.
For Locklizard and Digify:
Safeguard Web Viewer is a no installation browser based Viewer. It enables protected PDF files processed by Web Publisher to be viewed in a browser from any device using any Operating System. It is ideal for environments where no Viewer software can be installed. Safeguard Web Viewer solves the issues of firewall access, granting administrator privileges, and the use of roaming profiles. It does not rely on insecure plug-ins, self-extracting exes.

Then Digify:
Access control
Decide whether you want to make your files accessible publicly or only to invited recipients.​ Restrict forwarding
Decide whether to allow or restrict recipients from being able to forward your files to someone else. Revoke access
Have the option to revoke access to a file in case of errors or if files were sent to the wrong person.​ Most formats supported
Secure PDFs, images, videos, or special files that need a specific software with Digify. Print & download permissions
With integrated digital rights management, your files are by default for viewing only, no copy is stored in the recipient’s device. You decide whether to allow print or download. Passkey encryption
For “zero provider knowledge” protection, you can opt to apply secondary encryption on your important files using your own password or passkey.
Both platform is using library of pdf.js and slightly cheaper than Adobe. Besides web version of displaying pdf, locklizard also introduce a file format call pdc, which is just a encode file of pdf in my study, thier viewer software translate the encoded bits like base64 into pdf file, and then display the file in their installed viewer.

MaiPDF made the thing simpler and free.
User can share pdf in webview format and without any registration process!
User can also have HTML format of file to share around which do not require extra software installation!
MaiPDF can do what these provider can do, but also cannot do what these provdier cannot do!!! except by developing Google Glass, there is no way to prevent screen recording or photograph.

Chania MaiPDF Encryptor uses the strongest possible industry-standard encryption to protect your documents from copying and forwarding, online and offline, before and after delivery. Our access controls go a step further by enabling document expiration, location-based access, and printing restrictions. Importantly, your documents and the keys to them never leave your possession.

Chania A strong document security system is worthless if your authorized users can't access their documents. Because MaiPDF is designed to operate within industry-standard viewers, users seldom run into problems with secured documents being blocked by antivirus and other firewall software since it is based on HTML(simple web pages). Users do NOT need to download any plugin or software,both online and offline DRM-PDF are able to be opened in any modern Browsers.

List of MaiPDF's Features
Brief introduction of tools
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Free but powerful to protect your pdf files
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Easy to share your file with a Link
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Quick view of restriciton settings
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