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Participant B spoke at length
with cardiologists at a major
m e d i c a l c e n t e r, t a l k e d
briefly with a medical laboratory, received calls from a pharmacy, and placed short calls to
a home reporting hotline for a
medical device used to monitor
cardiac arrhythmia.
■■ Participant C made a number
of calls to a firearms store that
specializes in the AR semiautomatic rifle platform. They also
spoke at length with customer
service for a firearm manufacturer that produces an AR line.
■■ In a span of three weeks, Participant D contacted a home
improvement store, locksmiths,
a hydroponics dealer, and a
head shop.
■■ Participant E had a long early
morning call with her sister.
T wo days later, she placed
a series of calls to the local
Planned Parenthood location.
She placed brief additional calls
two weeks later, and made a
final call a month after.
That's a multiple sclerosis sufferer, a heart attack victim, a semiautomatic weapons owner, a home
marijuana grower, and someone
who had an abortion, all from a
single stream of metadata.
Web search data is another
source of intimate information that
can be used for surveillance. (You
can argue whether this is data or
metadata. The NSA claims it's metadata because your search terms are
embedded in the URLs.) We don't
lie to our search engine. We're
more intimate with it than with our
friends, lovers, or family members.
We always tell it exactly what we're
thinking about, in as clear words as
possible. Google knows what kind
of porn each of us searches for,
■■

which old lovers we still think about,
our shames, our concerns, and our
secrets. I used to say that Google
knows more about what I'm thinking
than my wife does. But that doesn't
go far enough. Google knows more
about what I'm thinking than I do,
because Google remembers all of it
perfectly and forever.
I did a quick experiment with
Google's autocomplete feature.
This is the feature that offers to
complete typing your search queries in real time, based on what
other people have typed. When I
typed "should I tell my w," Google
suggested "should i tell my wife i
had an affair" and "should i tell my
work about dui" as the most popular completions. Google knows who
clicked on those completions, and
everything else they ever searched.
Google's CEO Eric Schmidt
admitted as much in 2010: "We
know where you are. We know where
you've been. We can more or less
know what you're thinking about."
If you have a Gmail account,
you can check for yourself. You can
look at your search history for any
time you were logged in. It goes
back for as long as you've had the
account, probably for years. Do it;
you'll be surprised. It's more intimate than if you'd sent Google your
diary. And while Google lets you
see it, you have no rights to delete
anything you don't want there.
There are other sources of
intimate dat a a nd met adat a.
Records of your purchasing habits
reveal a lot about who you are.
Your Tweets tell the world what
time you wake up in the morning, and what time you go to bed
each night. Your buddy lists and
address books reveal your political
affiliation and sexual orientation.
Your email headers reveal who

IEEE Technology and Society Magazine

is central to your professional,
social, and romantic life.
One way to think about it is that
data is content, and metadata is
context. Metadata can be much
more revealing than data, especially when collected in the aggregate. When you have one person
under surveillance, the contents of
conversations, text messages, and
emails can be more important than
the metadata. But when you have
an entire population under surveillance, the metadata is far more
meaningful, important, and useful.
As former NSA General Counsel Stewart Baker said: "Metadata
absolutely tells you everything about
somebody's life. If you have enough
metadata you don't really need content." In 2014, former NSA and CIA
director Michael Hayden remarked:
"We kill people based on metadata."
The truth is, though, that the difference is largely illusionary. It's all
data about us.

Author Information
Bruce Schneier is an American cryptographer, computer security and privacy
specialist who has written several
books on security and cryptography.
He is based in Minneapolis, MN,
and can be reached at schneier@
schneier.com.

Acknowledgment
This keynote was adapted from the
author's book, Data and Goliath:
The Hidden Battles to Collect Your
Data and Control Your World," published in 2015.

References
[1] J. Mayer and P. Mutchler, MetaPhone: The
sensitivity of telephone metadata," Web
Policy, Mar. 12, 2014; http://webpolicy.
org/2014/03/12/metaphone-the-sensitivityof-telephone-metadata/.

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september 2015

http://webpolicy

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