Restricting Access to Documents
In some cases you may want to protect your documents in Print2Flash format with sensitive
information from printing, copying text from it or from
viewing it. The best results are achieved with Flash document protection.
However, Print2Flash provides similar features for HTML5 documents as well.
Protection from Printing
To prevent document viewers from printing the converted document
you need to set Disable Printing checkbox in
Protection Tab of Document Options window before document conversion. This option automatically disables Print
button on the document toolbar as well as disable access to print function with
keyboard shortcuts or using Print2Flash
At programmatic conversion you can disable printing by setting
PROTDISPRINT flag in the ProtectionOptions property of
Profile object or in the ProtectionOptions
Enhanced Batch Processing.
Protection from Copying Text
prevent document viewers from copying text from the converted document
you need to set Disable Text Copying By User checkbox in
Protection Tab of Document Options window before document conversion. This option automatically disables
Select Text button on the document toolbar. If you want
to disable text copying using Print2Flash
Document API, you need to set Disable Text Copying With Document API option
in the same window.
At programmatic conversion you can disable text copying by setting
PROTDISTEXTCOPY and PROTDISTEXTCOPYAPI flags
in the ProtectionOptions property of Profile
object or in the ProtectionOptions parameter of
Enhanced Batch Processing.
Protection from Viewing
Print2Flash documents are just regular Flash or SVG files that can be downloaded and
shown in a web browser. Like any other kind of files they cannot prevent
themselves from copying or downloading by external software. So usually if a
user views a standard Print2Flash document in the browser or Flash Player, it means this
document is already somewhere on disk and user can in principle re-open
and view this document as many times as he wishes. If this is not what you
intended, it may present a problem for you. Fortunately Print2Flash provides
some kind of solution to this problem.
Protection from Storing of Documents in Browser Cache
Usually web browsers store downloaded resources including Print2Flash
documents on disk to provide faster document retrieval when you open this
document the next time. The area where such resources are stored is called browser cache.
If you intention is to show documents only online in browser, you may be
concerned that the documents already viewed by user are stored on disk. It means
that an intelligent user can find a document in the cache, retrieve it from
there and open it. However, you may prevent caching in browser by sending
these HTTP headers when returning Print2Flash documents from your web server:
This will make common browsers complying with standards such as Internet Explorer or Firefox not to
cache the documents.
Expires: Mon, 26 Jul 1997 05:00:00 GMT
However, note that there are offline browsers that always cache downloaded
files regardless of the headers.
Restricting Access to Documents by Domain
achieve additional protection if you allow your documents to be viewed only when
they are downloaded in the browser or Flash Player from your site (domain). If a user
stores this document on disk or retrieves it from disk cache or uploads it to
another web site, this protection technique will not allow this document to be
shown in these cases. Thus your documents appear to be "linked" to your site
without a possibility to view them from other sites or disk.
To restrict access to documents by domain, you need to specify a list of
allowed domains in the Protection tab of
Document Options window. Then when you convert documents with Print2Flash,
this list is stored inside Print2Flash documents and used to check if access to
document should be granted. When a protected document is opened, it checks the
domain it has been loaded from and, if it matches one of the domains specified
in the allowed list, the document is displayed to the user. Otherwise, the
document is not displayed
For example, if your Print2Flashdocuments are to be served only from your site
with mysite.com domain, you need to add that domain to the allowed domain list.
The effect of this will be the documents can be shown only when they are
downloaded from this site (from a URL having "mysite.com" in its domain part).
If this document is stored on disk or viewed from disk cache, the document will
not be shown. If this document is uploaded to another site, it will not be shown
from there either.
At programmatic conversion you can specify this allowed domains list using
RestrictionDomains property of Profile object or in the RestrictionDomains
Enhanced Batch Processing.
The domain restriction technique is good enough but documents can still be
shown offline in some offline browsers or other software that can fake the
loading domain. For example, if an offline browser cached the document
(regardless of the HTTP headers mentioned above) and loads it in the browser or Flash
Player making it think that the document is loaded from an original allowed site
it was downloaded earlier from, the document will still be shown as the document
has no way to know if it has been downloaded from cache in such a case.
Therefore, the most reliable technique would be making the document send a
request to your web server each time a document is opened asking it for
permission to display the document. This way your server will be in complete
control of when and to whom the access to your documents is allowed. This
requires a custom approach and some implementation on your server (the script
answering viewing permission requests).
Please contact our support if you are interested in such kind of solution
sending us a description of your document protection requirements. We might
provide you with a custom solution tailored to your needs.