There’s an even bigger problem
And it’s even worse than that — much worse.
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There is no technology that can prevent someone from forwarding or copying a message you’ve sent them. Worse yet, in most cases, it’s also impossible to prevent them from modifying your message when it’s forwarded.
Out of your control
Once you’ve sent a message, it’s gone, and you lose all control over it. And by all control, I mean:
- You cannot “unsend” it, or prevent recipients from reading it.
- You cannot reliably tell if it’s been received.
- You cannot reliably tell if it’s been read, deleted, or forwarded.
- You cannot prevent it from being forwarded, copied, or changed.
This applies to almost all message types: emails, text messages, and messages using dedicated messaging apps. (Some may allow you some control if you act quickly enough after sending your message, but it’s not something you can rely on.)
Note I said “reliably” in a couple of cases. There are simple tracking technologies for formatted email, sometimes allowing you to tell an email has been opened. This technique is not 100% accurate because mail clients have the feature turned off by default to protect your security and privacy.
And, of course, “opening” an email does not necessarily mean the email actually gets read or even seen by anyone.
It’s the last item in my list — “You cannot prevent it from being forwarded, copied, or changed” — that should concern you.
I’ll put it more clearly: you cannot prevent someone from changing what your message said before they forward it.
Get that? Not only can they forward your message, but they can change what your message says.
When someone forwards an email, for example, that email becomes the body of a new email, and can be edited before hitting Send. It could be as simple as changing a “yes” to a “no”, an “I love you” to a “Get out of my life”, or perhaps “The boss is a genius” to “The boss is an idiot.”
You get the idea. If you were concerned about your email being forwarded, you can be even more concerned now. You really do need to trust your recipients.
What to do?
If messaging and email are such unreliable media, what can you do?
Well, the simplest first step for this particular issue is to save all your outgoing messages. You’ll then have a record of what you really said.
Second, don’t say anything in email you wouldn’t want to be made public.
Third, if forwarding and/or modification is a concern at all, make sure you’re dealing with someone you trust.
There are technologies like cryptographic message-signing that allow tampering to be detected. Unfortunately, they’re generally used only by some businesses and the tech savvy.
To be honest, it shocks me how much sensitive information is transmitted in email and other messaging media without any protection whatsoever.1
I’m hopeful security and privacy solutions will get easier and more common. For now, though, if someone can read your messages, they can forward, copy, modify, and send it to anyone they choose.
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Footnotes & References
1: Other than the silly disclaimer boiling down to “If this message wasn’t intended for you, forget everything you just read.”