Encrypting with an message expiration date

[David Shaw]

On Jan 3, 2010, at 12:01 AM, Dan Mahoney, System Admin wrote:

> On Sat, 2 Jan 2010, David Shaw wrote:
>
>> On Jan 2, 2010, at 11:10 PM, Faramir wrote:
>>
>>> Allen Schultz escribió:
>>>> GnuPG-Users:
>>>> Is there a way to force an expiration date when encrypting a  
>>>> message
>>>> for additional security. I have a friend who is inquiring. I've
>>>> already informed him of the "for his/her eyes only" option.
>>> What is that option?
>>
>> --for-your-eyes-only
>>
>> But don't think it adds real security.  In OpenPGP, the FYEO option  
>> just sets a flag in the message that means (in effect), "Pretty  
>> please, with sugar on top, treat this as for your eyes only".  The  
>> recipient is free to ignore the flag and do whatever they like.
>
> Is that analagous to the flag in older versions of PGP that would  
> cause a message to be displayed in a non-printable/non-copyable  
> format?

It is more than analogous - it is that exact flag.  Even in old PGP,  
the flag was really just advisory.

David