Sender and receiver non-repudiation

[David Honig]

At 08:55 AM 7/3/01 -0700, Lynn.Wheeler at firstdata.com wrote:
>signing. With digital signatures it becomes murkier ... how does somebody
>know that what they are looking at is the same thing that the computer is
>calculating a digital signature for.

Good point.  There's no way without a trusted host somewhere.  

Imagine that you scanned the paper doc, inspected it visually,
and digitally signed the image file.  Even this is succeptible to
a trojan that alters the display, alters what's printed, etc.

If you do have a little trusted island, e.g., a java button
on a ring you wear in the shower, or a PDA display you trust, 
you can often leverage this to make a trusted system.  







 






  







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