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Wednesday, July 8, 2015

More about the NSA's XKEYSCORE

I've been reading through the 48 classified documents about the NSA's XKEYSCORE system released by the Intercept last week. From the article:
The NSA's XKEYSCORE program, first revealed by The Guardian, sweeps up countless people's Internet searches, emails, documents, usernames and passwords, and other private communications. XKEYSCORE is fed a constant flow of Internet traffic from fiber optic cables that make up the backbone of the world's communication network, among other sources, for processing. As of 2008, the surveillance system boasted approximately 150 field sites in the United States, Mexico, Brazil, United Kingdom, Spain, Russia, Nigeria, Somalia, Pakistan, Japan, Australia, as well as many other countries, consisting of over 700 servers.
These servers store "full-take data" at the collection sites -- meaning that they captured all of the traffic collected -- and, as of 2009, stored content for 3 to 5 days and metadata for 30 to 45 days. NSA documents indicate that tens of billions of records are stored in its database. "It is a fully distributed processing and query system that runs on machines around the world," an NSA briefing on XKEYSCORE says. "At field sites, XKEYSCORE can run on multiple computers that gives it the ability to scale in both processing power and storage."
There seems to be no access controls at all restricting how analysts can use XKEYSCORE. Standing queries -- called "workflows" -- and new fingerprints have an approval process, presumably for load issues, but individual queries are not approved beforehand but may be audited after the fact. These are things which are supposed to be low latency, and you can't have an approval process for low latency analyst queries. Since a query can get at the recorded raw data, a single query is effectively a retrospective wiretap.
All this means that the Intercept is correct when it writes:
These facts bolster one of Snowden's most controversial statements, made in his first video interview published by The Guardian on June 9, 2013.
You'll only get the data if it's in the NSA's databases, but if it is there you'll get it.
Honestly, there's not much in these documents that's a surprise to anyone who studied the 2013 XKEYSCORE leaks and knows what can be done with a highly customizable Intrusion Detection System. But it's always interesting to read the details.
Back to encryption and Mujahedeen Secrets. If you want to stay secure, whether you're trying to evade surveillance by Russia, China, the NSA, criminals intercepting large amounts of traffic, or anyone else, try not to stand out. Don't use some homemade specialized cryptography that can be easily identified by a system like this. Use reasonably strong encryption software on a reasonably secure device. If you trust Apple's claims (pages 35-6), use iMessage and Facetime on your iPhone. I really like Moxie Marlinspike's Signal for both text and voice, but worry that it's too obvious because it's still rare. Ubiquitous encryption is the bane of listeners worldwide, and it's the best thing we can deploy to make the world safer.

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