[cryptography] Math corrections
James A. Donald
jamesd at echeque.com
Mon Sep 19 02:06:24 EDT 2011
Marsh Ray wrote:
>> But the failure of *any* single CA allows a successful attack on *every*
>> user connecting to *every* https website.
On 2011-09-19 2:48 PM, Arshad Noor wrote:
> Would you care to explain this in more detail, Marsh?
> Please feel free to frame your explanation as if you were
> explaining this to a 6-year old.
Assume I have control over a CA, one obscure and minor CA that no one
has ever heard of, and hardly anyone uses. Perhaps I have hacked them.
Perhaps I am an Islamic preacher whose congregation is apt to blow up
those that displease me, due to their sadly regrettable misunderstanding
of Islam. Perhaps I am chief of police in some third world terror state
such as Iran. Perhaps I am someone important at Harvard, or someone
important in a Russian Mafia.
I want to intercept, and perhaps modify, all email to google. I get an
intercept going through any of the notorious flaws in major routers, so
that when a browser attempts to connect to https://mail.google.com, it
in fact connects to my server, which may then connect to the real
I have my obscure and minor CA issue me a certificate for
I intercept all communications between https://mail.google.com and Iran.
I have a keyword program check all the mail for bad words and
forbidden topics. Any Iranian who writes inappropriate thoughts in a
gmail gets tortured, and any Harvard student who writes inappropriate
thoughts in a gmail gets failed.
Heaven help the poor Harvard student who wrote to his friend that his
parents were giving him a niggardly allowance.
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