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General discussion

How to Deny Someone From Forwarding An Email You've Sent Him

Jun 19, 2007 3:37AM PDT

Hi Guys,

As the subject denotes, I would like to know whether it's possible to deny someone from forwarding an email that I've sent him myself earlier. In the sense that I have a file in PDF format which I need to attach in this email but since the PDF file contains sensitive data, I need ONLY the intended particular recipients to receive my email; in a way that these same intended recipients won't be able to forward my email to third parties. Similarly it's important that the recipients won't be able to copy this file on their Hard Disk [CHappy as then it will be very easy for them to forward the file as a new attachment in a new email.

Just to make it clear, the contents in the email itself are not a problem if they are copied and forwarded; my concern is only the PDF file attached, that is, how I can prevent the file I attached from being distributed to non-intended recipients or to third parties.

The PDF file attached I need to send is already in READ ONLY format and the recipients can't copy the contents by a simple COPY PASTE but my concern is still the one mentioed above as presently they still can forward my email to third parties.

In this regard, can someone help me out please? Maybe you know of a setting I can do in my email account settings or a software which can help me solve out my problem? Or maybe from Adobe Acrobat Professional itself...

Just to let you know, preferably I'd like to use my GMAIL account to send this email but please feel free if there's a solution related to other email programs other than Web-based e-mail services like Gmail.

I thank you in advance for any comments and assistance.

Best Regards,

Corolla

Discussion is locked

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my advice would be
Jun 19, 2007 3:40AM PDT

send the PDF file as an attachment in a second email (possibly with a note asking that it not be forwarded or shared?)...

jonah

.,

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come on..........!!
Jun 19, 2007 3:59AM PDT

It's like I'm telling them please forward my email...Happy

thanks anyway

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The only way this can be done is
Jun 19, 2007 4:03AM PDT

to encrypt the email. You need to have a digital signature and certificate.

Not sure much about that information.

You send emails

Most people will forward them

Your email address travels with it

Keep a special email account for your fun things

Keep an email account for your personal use

Make an email account for newsletters

If you have a website, make an email account for the website only.


Your email address will be posted in almost every email forwarded. A spammer will eventually get your email address and try to spam you. This is why you need to keep things seperate.

Remember once you put things into writing, email or whatever, anyone can see your information.

Best advise...

Don't put anything into an email that you don't want anyone else to read. If you want to send someone an email and talk about me, remember the email might get back to me. You would not like that, so don't do that to others.

Never do an email in angry.

You might be able to send the email in bitmap format. Some people cannot forward bitmaps very well. They tend to leave blank squares.


If it's very important and work related, then you need a digital signature and certificate and need to encrypt the email.


I also remember that there was a program, you put your document into it. Add a password. The person on the other end needs a password to open the folder. I don't remember the name of the program.


Hope this helps.


Rick

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Secure attachments
Jun 23, 2007 1:44AM PDT

You don't remember the name of the program where you put your document(s) into it and add a password. The person on the other end needs a password to open the folder.
That's WINZIP. You must check the password option and enter a password as you create a ZIP file. Nobody can get into the files without that same password.
It also works as a security measure on your own computer. People exploring your files will hit a dead end at this file. I do that on mine, just as I do with everything in OutLook.
Put all files to be attached to an e-mail into a secure ZIP file and attach the ZIP to the e-mail, instead. Give them the password some other way. Don't put the password into that e-mail!
You can access WINZIP from your explorer with a right click on the file(s) to be zipped. It's obvious from there, but you are best off using the "Zip and e-mail plus" selection.
As all these other replies said, you can't stop anybody from making a copy. However, extra steps are needed this way. You can make it tougher by choosing a password that they would forget within 10 seconds. How about "5yP4cX27z0o1". That's a zero, not an oh. They must match the case of each letter, too!

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So...
Jun 23, 2007 2:17AM PDT

What's stopping the person from simply passing the password along to someone else, or someone else using a password cracking program on the archive?

Passwords and the like really only stop the honest people. Someone who wants to get something for free (or at least a greatly reduced price) will find a way. That's just how things are in the real world.

The game console industry is a great example of this. The early cartridge based systems required special hardware to be able to read the data off the cartridges, but that didn't stop people from making ROM dumps and working on emulators. Then there was a shift made to using CD/DVD media instead, and special codes were inserted into original game discs that couldn't be duplicated. And so was born the modchip, which originally just tricked the system into always thinking it was reading a commercial game disc. Later that whole system was bypassed. If you look at the original Xbox, people have taken the firmware and hacked it to add new features and remove security checks. Then there's what was done with the PSP. A workable exploit found in a specific firmware version is how one custom firmware maker bootstraps later firmwares, so people can have the best of both worlds. With the Xbox 360, people have attacked the DVD drive's firmware to trick it into reading burned discs.

You could also follow the huge amounts of money the movie and music industry have pumped into various protection systems. The latest system, used to protect HD-DVD and Blu-Ray discs cost several million dollars to develop, and lasted all of about 3 months before it was cracked. The supposed advantage of this new system is it has a system for revoking keys if they're cracked, but then within about 24 hours of issuing a new key, it was once again cracked.

It's an impossible battle to win. Nothing you do will stop a sufficiently motivated person. Trying to increase the pain in the *** level really only serves to annoy and punish those you WANT to be able to access the content.

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You can't
Jun 19, 2007 4:39AM PDT

All you can do is ASK the person not to forward things along, but there's no means to prevent them from doing so if they are so inclined.

This is the same problem the movie and music industry is trying to come to grips with on DRM (digital rights management). If someone else can read/watch/listen to it, it can be forwarded/copied, and that's all there is to it.

You can try adding a legal notice at the end of messages, so you could potentially sue the person after the fact if they send it to others, but it really doesn't do much about the issue of other people having copies of the PDF in question. You can try tracking them down and suing them, but they may have sent the file on to yet more people, and it can quickly balloon completely out of control.

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non-disclosure agreement
Jun 19, 2007 7:49AM PDT

you need to get the recipient to agree to an NDA. it won't stop him/her from forwarding the confidential document, but you will have legal recourse.

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I've no idea, However...
Jun 22, 2007 10:51AM PDT

it would surprise me if some enterprising soul hasn't devised a means whereby such a message might be made to "self destruct" when opened by anyone but the original addressee. And I know there are means of preventing some documents from being copied, or saved to their HD, though I've only seen them in PSP type programs myself

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Secure PDF
Jun 22, 2007 11:50AM PDT

I have no idea how it is done, but I purshased some building plans online. The plans were sent to my in pdf format,but I had to enter a code in order to open the file. If I remember correctly the file could only be opened one time. I had to print it to keep the plans. I am not sure if that is an option when creating pdf files. I have limited experience with that. Hope it helps.

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One problem with that
Jun 22, 2007 12:58PM PDT

It all depends on the PDF reader program to honor those security measures. Adobe's reader program will obviously, but they can't make third party readers, like Foxit Reader and Xpdf, respect them.

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They could still be scanned
Jun 27, 2007 1:40AM PDT

after being printed, and then passed on to a number of people.

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Give kablooeymail a try
Jun 25, 2007 2:04AM PDT

Take a look at www.kablooeymail.com. Free e-mail that will self-destruct after being read by the recipient. This is pretty cool.

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I say it can't be done.
Jun 22, 2007 11:47AM PDT

Contrary to what people may have learned from watching X-Files, anything that can be seen can be copied. Even if you could prevent them from saving or forwarding the message, they could still do a screen capture, take a snapshot of the screen with a camera, or just type it up as a new document.

About the best you could hope to do is send each recipient a slightly different version of the document, so that if a leaked version shows up you'll know who's guilty.

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I Agree
Jun 22, 2007 7:32PM PDT

If someone wants to forward it bad enough then they will, there is ALWAYS a way

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Yep
Jun 27, 2007 1:43AM PDT

I read that map makers put a little bit if fake stuff in their maps so if somebody copies them, they will know.

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USE Secure Email
Jun 22, 2007 11:58AM PDT
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Or....
Jun 22, 2007 12:05PM PDT

Try www.bigstring.com It has options for
Self-Destructing
Recallable/erasable email
Non-Forwardable/IP Locking
Non-Printable/savable emails
Advanced Email Tracking
Masquerading

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Yes you can ...
Jun 23, 2007 3:09AM PDT

in addition to bigstring.com you can use a product such as SafeMessage http://www.safemessage.com

SafeMessage is priced around $100 which is expensive if you have no need for such but really cheap if you do have such a requirement.

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Get Adobe Acrobat Full Version
Jun 24, 2007 10:44AM PDT

The full version of Adobe Acrobat has security measures that can be used to protect your PDF files. However, the program is a little pricey. If this is for where you work, get the company to purchase the software.

However, as others have mentioned, there may be ways to sidestep this protection. I remember years ago a company I worked for was using LotusNotes for email, but one particular person sent all of their emails with copy protection so it couldn't be printed, copied, or forwarded. The manager I was working for wanted to print it out so I figured out a way to do it very successfully. I only did it as a test to see if it could be done. LotusNotes was, and probably still is, a terrible database and email program.

I wouldn't trust any email program to be secure especially in the business environment. Also, sending proprietary information from a company via email is not always the best solution. If it's a private file, and I don't feel comfortable sending it out to someone who might use it inappropriately, I just don't send it.

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Re: forwarding email
Jun 27, 2007 7:13AM PDT

Coralla,

Even if you could find a way to inhibit the forwarding of the message (I didn't study the links provided by some members above, although I've got some doubts about it, but they might be right) consider the following scenario.

1. Recipient opens the message in Outlook Express.
2. Recipient opens the attachment.
3. Recipient closes the attachment after reading it.
Not unreasonable till here, I'd say.
4. Recipient goes to Temporary Internet Files and copies the attachment that Outlook Express conveniently stored there in step 2 to his own My Documents.
All he has to know is to look there, and that's common knowledge.
5. Recipient is free to do with it what he wants. Such as sending it to somebody else.
Nothing you can do against it IMO. Sorry for that.

Waiting for somebody to explain why this shouldn't work.

Kees

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With bigstring.com ...
Jun 28, 2007 8:24AM PDT

the file is read form the bigstream server and not cached and with safemessage again there is no caching.

A screenshot is about the only way around such which makes the message a graphic and any editing is obvious. If the attachment is set for one time viewing even the screenshot becomes improbable although not impossible.

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Thanks for this explanation.
Jun 28, 2007 6:20PM PDT

So it's possible indeed.

Kees

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Yep, just like you can use ...
Jun 29, 2007 3:59AM PDT

a metatag on your own web pages to prevent their being cached:

<meta http-equiv="pragma" content="nocache">

(works best when used in both the header and again AFTER the body:

<HTML>
<HEAD>
<TITLE>---</TITLE>
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
</HEAD>
<BODY>

Text in the Browser Window

</BODY>
<HEAD>
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
</HEAD>
</HTML>

NOTE: to make sure that nothing is cached if the viewer is using MSIE 5 add another tag each place:

<META HTTP-EQUIV="Expires" CONTENT="-1">

for preventing Navigator from cacheing also include this javascript in the body tag:

onLoad="if ('Navigator' == navigator.appName) document.forms[0].reset();"

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Thanks A Lot
Jul 10, 2007 12:30AM PDT

Hi Guys,

First of all I'd like to thank you all for your replies to this topic - I really appreciate in trying to help me out but maybe what I'm asking for is in a way impossible.

I've tried the various specified email secured web based services suggested such as hushmail, bigstring, etc. but none of them met my needs. Actually I can't use a self-destructing option as that's not a solution for me - I want a particular intended recipient to keep the email on his PC only- no prob. However what I don't want is for the email not to be forwarded to 3rd parties I don't even know! The web-based email account which I thought can help me out was bigstring. In fact it clearly specifies in the product description that there's a non forwardable option. In fact that's what I want! However when I tried and tested it myself - the attached document can still be forwarded to another address without any problem although you specify in the option before sending the email not to be forwarded. However appparently this option doesn't work or else if it does I'm missing something. In this case if someone manages to do so please let me know.

I've read all replies but to tell you the truth I couldn't follow the "very technical-related" replies as I'm not into programming. But I'm more than sure it must have been useful to someonelse-which is obviously very good!

Thanks for your time and assistance.

Best Regards to all,

Corolla

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Did you try SafeMessage?
Jul 10, 2007 3:18AM PDT
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How much is it worth?
Jul 10, 2007 10:35PM PDT

There are some expensive programs, such as Lock Lizard Safegaurd that can protect your documents by preventing copies, time expiration...

The problem with PDF's is that they can be opened with many programs and the security depends on which program is used to open the file. Adobe has also destroyed the integrity of their own program by allowing you to cut from PDF and paste to another program. Sure it's not the original but they have essentially a duplicate.

Sounds like your security problem is with the people you send the email and with screen capture programs, almost anything can be printed.

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limited access for emailed files
Dec 18, 2015 4:37PM PST

Hey Corolla,

I read what you are trying to do and I am in the same situation. I need a program which will allow me to send a file and that file is locked to being forwarded by the recipient. It is also locked from screen captures and from copying. Finally, it can self destruct if one wants that. The program which supposedly will do all the above is by a company called DIGIFY. I have done a limited trial with it and found some of the stuff is very true but I still have some problems with some features. Still, I think you might want to look into it because it is quite easy to use and promises to do all the things you require. Check it out at www.digify.com

Richard

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I blew past that issue by pointing my camera at the screen.
Dec 18, 2015 6:24PM PST

The more complicated they make it, the easier it is to get around it.