Read-Once Messages?

[Perry E. Metzger]

Lefty says:
> Has there been any work done on messages that can be read a single time,
> preferably only by a designated recipient, and is not amenable to being
> captured as it is "played"?  I know that Gibson's poem _Agrippa_ had some
> sort of self-destruct feature built into it, but I don't know what
> mechanism was used to implement this.
> 
> Any pointers or suggestions would be appreciated...

It might be possible, but only using hardware that can be broken. Any
algorithm can obviously be run as often as the recipient desires, and
in any case the recipient could simply save the output somehow (at
worst via videotape.) There are many things one would like to be able
to do like this that are sadly not possible.

Perry