CDR: RE: Re: why should it be trusted?
Ray Dillinger
bear at sonic.net
Tue Oct 17 12:57:22 PDT 2000
It occurs to me that the NSA may in fact have a much easier time
of cracking most encrypted messages than is generally believed by
the people who use them.
We can rule out the idea that they may have computers capable of
solving the ciphers by a brute force key search or modulus factoring
-- basically, such a computer would be at least the size of jupiter,
assuming complete mastery of nanotech. Since we can't see any such
objects within five or six light-days, that pretty much cooks the
"near real-time solving" of ciphers.
However, we are forgetting what they do have. They've got Echelon.
That means all kinds of intercepts, by and about the people
communicating, most of them in plaintext. They keep dossiers
on people that list vital statistics like birthdate, hometown,
grade school and high school classmates, parents, siblings,
neighbors, organizations, etc. They've got all our goofy quotes
from our usenet posts, and of course everything that anyone's
said on mailing lists like this one.
Since most people use passwords and passphrases that are some
chunk of personal information, their system may not have to crunch
very long to come up with the password used by a particular target.
Security sweeps are always finding people who used, eg, their
college ID number, their first girlfriend's name, the street
they lived on as a kid, their parents' address, names of
countries or cities or fictional or historical characters, or
even ghods help us their own drivers license number or SSN as a
password. The spooks tend to have all of this info in a nice
cross-indexed database, so they can start guessing on something
a hell of a lot easier than random keys.
If the NSA is using their resources effectively, and the key
generator uses an input password or passphrase instead of random
numbers, they may indeed be able to crack most 2048-bit RSA
messages, in near realtime, just by knowing all the details
about the people who sent them. This is not an attack on the
cipher, but it could have the same effect against most opponents
most of the time.
Witness the case of Rashael Keavy, an enterprising businesswoman
of San Francisco. In San Francisco, prostitution is considered
about on a par with jaywalking. Technically it's illegal, but
the cops, as a matter of policy, don't bother making arrests
unless there's a "real" crime, either against the pro or against
the john, involved. Ms. Keavy operated a ring of "outcall"
prostitutes, and unlike most people in such businesses, treated
her employees very well. Paid them $50K salaries, with bennies,
a four month annual vacation, and a comprehensive health plan,
according to the papers that covered the arrest. Anyway, when
she expanded her business to the south, she encountered San Jose,
where prostitution is actually considered a crime. A few months
later, when the San Jose police were trying to raise money for
something or other, she was arrested.
She kept her business records encrypted on a laptop, and used a
good cipher, and used some kind of file wipe utility -- so the
cops figured they'd have to get one of her employees to testify
against her -- but her employees, describing her as "a great
woman", "an american hero", and generally the best thing ever
to happen to them, flatly and unanimously refused to do so.
This by the way is what attracted the attention of the press.
Madams rarely inspire unconditional personal loyalty.
So the cops called in a "data recovery" specialist from the
FBI, and her laptop yielded up its secrets in short order.
Ms. Keavy is now serving five to ten. (or heck, this was a
couple years ago, she may be paroled by now). TANJ.
Now I don't know what happened here -- there are any number of
things that could have been done wrong in securing the laptop,
especially since it was done by someone whose primary business
was not cryptography.
She may have forgotten to erase one time. She may have erased
but failed to use her file wipe utility. The file wipe utility
might have been one of those wimpy naive ones that just writes
zeros over a file. The OS may have swapped the encryption program
into the swapfile at a moment when the key was in memory, where
they could just pick it off the disk later.
But, it's also plausible that they just made a copy of the
encrypted files, sent them off to the Fort, and let a million
dollars worth of hardware running with a dossier about her
whole damn life spend a few hours guessing her passphrase.
Did they break the cipher? No. Did they break the message?
You betcha.
Bear
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