Encrypt a file to prevent unwanted viewers?

This is what I would like to do:

Send a file through email so only that person can read it. I want to
prevent him from sending it to anyone. For his eyes only.

Is there an encryption program that can do that? I don't want a
password or anything like that. I want the receiver to not have to do
anything, but make it so if he forwards the email to someone else they
are not able to read it.

The file that I am sending through email is .doc. I was think of
sending PDF's though.

Re: Encrypt a file to prevent unwanted viewers?

josh.dylewski@gmail.com writes:

> This is what I would like to do:
>
> Send a file through email so only that person can read it.

PGP or GPG will do that with public/private keys, if you can get that
person to learn how to use those, generate a pub/private key pair, and
send you his public key so you can encrypt the message with his public
key.

Only he, with his private key, could decrypt that message.

> I want to prevent him from sending it to anyone. For his eyes only.

Now you've got a challenge.

> Is there an encryption program that can do that? I don't want a
> password or anything like that. I want the receiver to not have to do
> anything, but make it so if he forwards the email to someone else they
> are not able to read it.


Some mail clients like Lotus Notes have a "prevent forwarding" feature
that you can flag on messages. You both need to be using notes
though, and the feature is circumventable.

> The file that I am sending through email is .doc. I was think of
> sending PDF's though.

I'm afraid short of having a face to face meeting and patting them
down for a hidden recorder or wire, I'm not sure you can achieve what
you seek in a fool proof way.

Best Regards,
--
Todd H.
http://www.toddh.net/

Re: Encrypt a file to prevent unwanted viewers?

Todd H. wrote:
> josh.dylewski@gmail.com writes:
>
>> This is what I would like to do:
>>
>> Send a file through email so only that person can read it.

> I'm afraid short of having a face to face meeting and patting them
> down for a hidden recorder or wire, I'm not sure you can achieve what
> you seek in a fool proof way.


The best solution would be an administrative control such as a
non-disclosure agreement. There are no technical solutions that are
foolproof. Not that a non-disclosure agreement is foolproof but at least
you will have some form of redress.

Bogwitch.

Re: Encrypt a file to prevent unwanted viewers?

wrote in message
news:1184775159.122826.281560@j4g2000prf.googlegroups.com...

> The file that I am sending through email is .doc. I was think of
> sending PDF's though.

I'm not a Linux bigot or something like that, but I consider it pretty rude
to send a .doc file via email. MS Office files support VBA which allow a
file to do all sorts of nasty things, and email addresses are trivially
spoofed, so you are asking the recipient to take a big risk opening that
file.

If, as Todd suggests, you use PGP or something similar, you could at least
sign the file so he could be confident it came from you, but that would
require action and considerable learning on his part. The fact that you
want him to do nothing suggests that he might not be all that computer
literate, in which case it is even more inconsiderate to send him a .doc
since he doesn't even know what the risk is.

...

Re: Encrypt a file to prevent unwanted viewers?

josh.dylewski@gmail.com (07-07-18 16:12:39):

> Send a file through email so only that person can read it. I want to
> prevent him from sending it to anyone. For his eyes only.

This is impossible. Period.

If you're afraid that the receiver might forward your message, then
there is something wrong with your relationship, and probably you
shouldn't send that message at all.


Regards,
Ertugrul Söylemez.


--=20
Security is the one concept, which makes things in your life stay as
they are. Otto is a man, who is afraid of changes in his life; so
naturally he does not employ security.

Re: Encrypt a file to prevent unwanted viewers?

josh.dylewski@gmail.com wrote:
> This is what I would like to do:
>
> Send a file through email so only that person can read it. I want to
> prevent him from sending it to anyone. For his eyes only.
>
> Is there an encryption program that can do that? I don't want a
> password or anything like that. I want the receiver to not have to do
> anything, but make it so if he forwards the email to someone else they
> are not able to read it.
>
> The file that I am sending through email is .doc. I was think of
> sending PDF's though.

A quick Google search brought up http://www.bigstring.com/mail/main.php,
among others.

--
Notan

Re: Encrypt a file to prevent unwanted viewers?

Haha, Thanks for the reply. I don't think that would work to well, I
should of explained this better. Basically what I do is send a
proposal to a customer and I want that proposal protected. I send
probably 50 a year to people I really don't know, and that I don't
want them to have to do anything other than open the document. They
should know that it is protected, but once (if) it leave there
computer then it wont open.

Make any sense?

It seems like it is possible, once the document is opened it ties with
that computers address and only opens for that computer. That way if
he forwards it the receiver will not be able to open it. Seems
possible to me but I really don't know too much about whats out there.

Re: Encrypt a file to prevent unwanted viewers?

yeah, I do that now. I just want something so that they go, "Oh, he's
not joking" when they read that. If they get there IT guy on it and
unprotect it then that fine. I just want so form of protection so that
they can understand that I really don't want them to show it around.

On Jul 18, 1:07 pm, Bogwitch wrote:
> Todd H. wrote:
> > josh.dylew...@gmail.com writes:
>
> >> This is what I would like to do:
>
> >> Send a file through email so only that person can read it.
> > I'm afraid short of having a face to face meeting and patting them
> > down for a hidden recorder or wire, I'm not sure you can achieve what
> > you seek in a fool proof way.
>
> The best solution would be an administrative control such as a
> non-disclosure agreement. There are no technical solutions that are
> foolproof. Not that a non-disclosure agreement is foolproof but at least
> you will have some form of redress.
>
> Bogwitch.

Re: Encrypt a file to prevent unwanted viewers?

On Jul 18, 4:24 pm, "xpyttl" wrote:
> wrote in message
>
> news:1184775159.122826.281560@j4g2000prf.googlegroups.com...
>
> > The file that I am sending through email is .doc. I was think of
> > sending PDF's though.
>
> I'm not a Linux bigot or something like that, but I consider it pretty rude
> to send a .doc file via email. MS Office files support VBA which allow a
> file to do all sorts of nasty things, and email addresses are trivially
> spoofed, so you are asking the recipient to take a big risk opening that
> file.
>
> If, as Todd suggests, you use PGP or something similar, you could at least
> sign the file so he could be confident it came from you, but that would
> require action and considerable learning on his part. The fact that you
> want him to do nothing suggests that he might not be all that computer
> literate, in which case it is even more inconsiderate to send him a .doc
> since he doesn't even know what the risk is.
>
> ..

I know the customer and if they cant trust me then they would not make
it that far down the line of my process. I fully understand VBA and
although it warns you if a .doc has and script/macro many users shut
that off. Your point is taken, I have been leaning toward buying
acrobat and make them in there.

Re: Encrypt a file to prevent unwanted viewers?

josh.dylewski@gmail.com wrote:
> Send a file through email so only that person can read it. I want to
> prevent him from sending it to anyone. For his eyes only.

Forget that.

Yours,
VB.
--
"Es muss darauf geachtet werden, dass das Grundgesetz nicht mit Methoden
geschützt wird, die seinem Ziel und seinem Geist zuwider sind."

Gustav Heinemann, "Freimütige Kritik und demokratischer Rechtsstaat"

Re: Encrypt a file to prevent unwanted viewers?

On 2007-07-19, josh.dylewski@gmail.com wrote:
> Haha, Thanks for the reply. I don't think that would work to well,
> I should of explained this better. Basically what I do is send a
> proposal to a customer and I want that proposal protected. I send
> probably 50 a year to people I really don't know, and that I don't
> want them to have to do anything other than open the document.
> They should know that it is protected, but once (if) it leave
> there computer then it wont open.
>
> Make any sense?
>
> It seems like it is possible, once the document is opened it ties
> with that computers address and only opens for that computer. That
> way if he forwards it the receiver will not be able to open it.
> Seems possible to me but I really don't know too much about whats
> out there.

The problem is that you aren't really asking for traditional
encryption, you're asking for DRM. Like all software DRM systems,
this would be inherently circumventable: if the recipient can read
your data then he can ultimately copy it too, no matter how
difficult you try to make it for him. That's simply the way
computers work.

That said, Adobe Acrobat probably provides the closest to what
you're asking for in the form of its "encrypted PDFs", particularly
if you encrypt the document to the recipient's (Thawte, Verisign, or
whatever) signed x.509 key. Mind you, if the recipient is dedicated
enough then he or she will absolutely be able to send the file along
to somebody else (after decrypting it using GhostScript, etc.), but
not without a certain level of technical sophistication.

--
Mark Shroyer
http://markshroyer.com/

Re: Encrypt a file to prevent unwanted viewers?

On Thu, 19 Jul 2007, in the Usenet newsgroup comp.security.misc, in article
<1184847446.708817.181960@o61g2000hsh.googlegroups.com>,
josh.dylewski@gmail.com wrote:

>Basically what I do is send a proposal to a customer and I want that
>proposal protected. I send probably 50 a year to people I really don't
>know, and that I don't want them to have to do anything other than
>open the document. They should know that it is protected, but once (if)
>it leave there computer then it wont open.

You are trying to solve a _legal_ problem with a _technical_ solution.
Ain't gonna work. Making prospective customers jump through hoops is
not the best way to get business unless you're the only game in town,
in which case they may decide to find other means of entertainment..

>It seems like it is possible, once the document is opened it ties
>with that computers address and only opens for that computer. That way
>if he forwards it the receiver will not be able to open it. Seems
>possible to me but I really don't know too much about whats out there.

Tell me - how do you think I'm replying to your article? It's really
fairly simple, and you've probably done so many times. Hint: Cut/Paste

You can send the document with what-ever technical protection you wish,
but the recipient STILL has to be able to read the d4mn thing. If the
recipient can read it, they can copy it - even if that means taking a
camera and photographing the monitor they're viewing it on. There
really is more than one way to forward the contents of a document -
even one that you've created using a non-standard font. At least I
assume you want the recipient to be able to read it... I could be
wrong of course.

Discuss your problem with your legal advisor.

Old guy

Re: Encrypt a file to prevent unwanted viewers?

On Wed, 18 Jul 2007 16:12:39 -0000, josh.dylewski@gmail.com wrote:

> This is what I would like to do:
>
> Send a file through email so only that person can read it. I want to
> prevent him from sending it to anyone. For his eyes only.
>
> Is there an encryption program that can do that? I don't want a
> password or anything like that. I want the receiver to not have to do
> anything, but make it so if he forwards the email to someone else they
> are not able to read it.
>
> The file that I am sending through email is .doc. I was think of
> sending PDF's though.

Thx
--
skype:mranep
cell:813-610-2978; work:813-386-4500; work2:813-915-1663
Motto: Why face the world myself when my wife's skirt, it is so dark and
comfy under it?
Proclamation: "A man can have sex with sheep, cows and camels and so on.
However, he should kill the animal after he has his orgasm. He should
not sell the meat to the people in Nepal; Ok I did so beat me with a
Yeti dick.

Re: Encrypt a file to prevent unwanted viewers?

On Wed, 18 Jul 2007 16:12:39 -0000, josh.dylewski@gmail.com wrote:

> This is what I would like to do:
>
> Send a file through email so only that person can read it.

That's simple.

> I want to
> prevent him from sending it to anyone. For his eyes only.

Much more difficult if not impossible.

> Is there an encryption program that can do that? I don't want a
> password or anything like that. I want the receiver to not have to do
> anything,

Usually these are self-extracting .exe files which are problematic in
themselves.

> but make it so if he forwards the email to someone else they
> are not able to read it.
>
> The file that I am sending through email is .doc. I was think of
> sending PDF's though.

There are several services which will track your doc when it is
forwarded, I have used one (maybe it was a PDF come to think of it)

http://www.readnotify.com/readnotify/text/info.asp

with success and it does have a email-destroying option.