Barry Leiba wrote:
Or using the same body in multiple messages. Suppose "Company I", say,
is sending a (legitimate, opted-into) mass-mailing of a 70 MB video file
to, say, 200,000 opted-in recipients. Suppose also that for some reason
it has to batch these with different headers, so it can't just sign the
whole message once. Saving the work of hashing that 70 MB video
multiple times would be nice.
70Mb video over SMTP? ::shudder::
> I suspect that the RSA signing operation overwhelms the
SHAx cost by a very good bit on your average size of body.
But that doesn't matter, because we're not RSA-signing the body, only
the hash. So it's only the overhead of the hashing that matters.
But you'd assumedly need a new RSA signature per message in order
for this to make any sense. To be pedantic:
CostRSAsign = 1
CostSHAx = .1
For message one, cost = 1.1, for message 2-n, cost = 1.0/msg -- big
whoop. These aren't accurate, just illustrative.
Mike
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