Fwd: crypto flaw in secure mail standards

[Anthony E. Greene]

On Mon, 25 Jun 2001, Don Davis wrote:

>>On Sun, 24 Jun 2001, David Shaw wrote:
>>> It is thus possible for Alice to send a signed and encrypted mail to
>>> Bob, Bob decrypts it, recovering the clearsigned message, and then
>>> re-encrypts it to Charlie.  Charlie will receive the original document
>>> with Alice's signature intact.
>
>Anthony Greene replied:
>> The encryption in this example is beside the point and in fact is a
>> distraction to the primary argument; that signed data can be taken out o=
f
>> context, given sufficiently vague data and a forgeable delivery mechanis=
m.
>
>for na=EFve users (my paper's focus), encryption is pivotal:
>their ignorance of PKI subtleties misleads them into
>thinking that forwarding a signed-&-encrypted message
>is impossible, when of course with secure-mail crypto,
>forwarding is straightforward.  with a signed plaintext
>delivery, Charlie might more readily see and understand
>that Alice's signed message doesn't refer to him.
>
>=09=09=09=09=09- don davis, boston

I see, but as has been pointed out, that problem exists with paper, and is
not really a software problem.

Tony
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