** **

How to remain secure against NSA surveillance****

http://www.theguardian.com/world/2013/sep/05/nsa-how-to-remain-secure-surveillance
****

** **

****

The NSA has huge capabilities - and if it wants in to your computer, it's***
*

in. With that in mind, here are five ways to stay safe****

        Bruce Schneier            ****

        theguardian.com, Thursday 5 September 2013 15.06 EDT         ****

** **

Now that we have enough details about how the NSA eavesdrops on the****

internet, including today's disclosures of the NSA's deliberate weakening of
****

cryptographic systems, we can finally start to figure out how to protect****

ourselves.****

** **

For the past two weeks, I have been working with the Guardian on NSA****

stories, and have read hundreds of top-secret NSA documents provided by****

whistleblower Edward Snowden. I wasn't part of today's story - it was in****

process well before I showed up - but everything I read confirms what the***
*

Guardian is reporting.****

** **

At this point, I feel I can provide some advice for keeping secure against**
**

such an adversary.****

** **

The primary way the NSA eavesdrops on internet communications is in the****

network. That's where their capabilities best scale. They have invested in**
**

enormous programs to automatically collect and analyze network traffic.****

Anything that requires them to attack individual endpoint computers is****

significantly more costly and risky for them, and they will do those things*
***

carefully and sparingly.****

** **

Leveraging its secret agreements with telecommunications companies - all the
****

US and UK ones, and many other "partners" around the world - the NSA gets***
*

access to the communications trunks that move internet traffic. In cases****

where it doesn't have that sort of friendly access, it does its best to****

surreptitiously monitor communications channels: tapping undersea cables,***
*

intercepting satellite communications, and so on.****

** **

That's an enormous amount of data, and the NSA has equivalently enormous****

capabilities to quickly sift through it all, looking for interesting****

traffic. "Interesting" can be defined in many ways: by the source, the****

destination, the content, the individuals involved, and so on. This data is*
***

funneled into the vast NSA system for future analysis.****

** **

The NSA collects much more metadata about internet traffic: who is talking**
**

to whom, when, how much, and by what mode of communication. Metadata is a***
*

lot easier to store and analyze than content. It can be extremely personal**
**

to the individual, and is enormously valuable intelligence.****

** **

The Systems Intelligence Directorate is in charge of data collection, and***
*

the resources it devotes to this is staggering. I read status report after**
**

status report about these programs, discussing capabilities, operational****

details, planned upgrades, and so on. Each individual problem - recovering**
**

electronic signals from fiber, keeping up with the terabyte streams as they*
***

go by, filtering out the interesting stuff - has its own group dedicated to*
***

solving it. Its reach is global.****

** **

The NSA also attacks network devices directly: routers, switches, firewalls,
****

etc. Most of these devices have surveillance capabilities already built in;*
***

the trick is to surreptitiously turn them on. This is an especially fruitful
****

avenue of attack; routers are updated less frequently, tend not to have****

security software installed on them, and are generally ignored as a****

vulnerability.****

** **

The NSA also devotes considerable resources to attacking endpoint computers.
****

This kind of thing is done by its TAO - Tailored Access Operations - group.*
***

TAO has a menu of exploits it can serve up against your computer - whether**
**

you're running Windows, Mac OS, Linux, iOS, or something else - and a****

variety of tricks to get them on to your computer. Your anti-virus software*
***

won't detect them, and you'd have trouble finding them even if you knew****

where to look. These are hacker tools designed by hackers with an****

essentially unlimited budget. What I took away from reading the Snowden****

documents was that if the NSA wants in to your computer, it's in. Period.***
*

** **

The NSA deals with any encrypted data it encounters more by subverting the**
**

underlying cryptography than by leveraging any secret mathematical****

breakthroughs. First, there's a lot of bad cryptography out there. If it****

finds an internet connection protected by MS-CHAP, for example, that's easy*
***

to break and recover the key. It exploits poorly chosen user passwords,****

using the same dictionary attacks hackers use in the unclassified world.****

** **

As was revealed today, the NSA also works with security product vendors to**
**

ensure that commercial encryption products are broken in secret ways that***
*

only it knows about. We know this has happened historically: CryptoAG and***
*

Lotus Notes are the most public examples, and there is evidence of a back***
*

door in Windows. A few people have told me some recent stories about their**
**

experiences, and I plan to write about them soon. Basically, the NSA asks***
*

companies to subtly change their products in undetectable ways: making the**
**

random number generator less random, leaking the key somehow, adding a****

common exponent to a public-key exchange protocol, and so on. If the back***
*

door is discovered, it's explained away as a mistake. And as we now know,***
*

the NSA has enjoyed enormous success from this program.****

** **

TAO also hacks into computers to recover long-term keys. So if you're****

running a VPN that uses a complex shared secret to protect your data and the
****

NSA decides it cares, it might try to steal that secret. This kind of thing*
***

is only done against high-value targets.****

** **

How do you communicate securely against such an adversary? Snowden said it**
**

in an online Q&A soon after he made his first document public: "Encryption**
**

works. Properly implemented strong crypto systems are one of the few things*
***

that you can rely on."****

** **

I believe this is true, despite today's revelations and tantalizing hints of
****

"groundbreaking cryptanalytic capabilities" made by James Clapper, the****

director of national intelligence in another top-secret document. Those****

capabilities involve deliberately weakening the cryptography.****

** **

Snowden's follow-on sentence is equally important: "Unfortunately, endpoint*
***

security is so terrifically weak that NSA can frequently find ways around***
*

it."****

** **

Endpoint means the software you're using, the computer you're using it on,**
**

and the local network you're using it in. If the NSA can modify the****

encryption algorithm or drop a Trojan on your computer, all the cryptography
****

in the world doesn't matter at all. If you want to remain secure against the
****

NSA, you need to do your best to ensure that the encryption can operate****

unimpeded.****

** **

With all this in mind, I have five pieces of advice:****

** **

1) Hide in the network. Implement hidden services. Use Tor to anonymize****

yourself. Yes, the NSA targets Tor users, but it's work for them. The less**
**

obvious you are, the safer you are.****

** **

2) Encrypt your communications. Use TLS. Use IPsec. Again, while it's true**
**

that the NSA targets encrypted connections - and it may have explicit****

exploits against these protocols - you're much better protected than if you*
***

communicate in the clear.****

** **

3) Assume that while your computer can be compromised, it would take work***
*

and risk on the part of the NSA - so it probably isn't. If you have****

something really important, use an air gap. Since I started working with the
****

Snowden documents, I bought a new computer that has never been connected to*
***

the internet. If I want to transfer a file, I encrypt the file on the secure
****

computer and walk it over to my internet computer, using a USB stick. To****

decrypt something, I reverse the process. This might not be bulletproof, but
****

it's pretty good.****

** **

4) Be suspicious of commercial encryption software, especially from large***
*

vendors. My guess is that most encryption products from large US companies**
**

have NSA-friendly back doors, and many foreign ones probably do as well.****

It's prudent to assume that foreign products also have foreign-installed****

backdoors. Closed-source software is easier for the NSA to backdoor than****

open-source software. Systems relying on master secrets are vulnerable to***
*

the NSA, through either legal or more clandestine means.****

** **

5) Try to use public-domain encryption that has to be compatible with other*
***

implementations. For example, it's harder for the NSA to backdoor TLS than**
**

BitLocker, because any vendor's TLS has to be compatible with every other***
*

vendor's TLS, while BitLocker only has to be compatible with itself, giving*
***

the NSA a lot more freedom to make changes. And because BitLocker is****

proprietary, it's far less likely those changes will be discovered. Prefer**
**

symmetric cryptography over public-key cryptography. Prefer conventional****

discrete-log-based systems over elliptic-curve systems; the latter have****

constants that the NSA influences when they can.****

** **

Since I started working with Snowden's documents, I have been using GPG,****

Silent Circle, Tails, OTR, TrueCrypt, BleachBit, and a few other things I'm*
***

not going to write about. There's an undocumented encryption feature in my**
**

Password Safe program from the command line); I've been using that as well.*
***

** **

I understand that most of this is impossible for the typical internet user.*
***

Even I don't use all these tools for most everything I am working on. And***
*

I'm still primarily on Windows, unfortunately. Linux would be safer.****

** **

The NSA has turned the fabric of the internet into a vast surveillance****

platform, but they are not magical. They're limited by the same economic****

realities as the rest of us, and our best defense is to make surveillance of
****

us as expensive as possible.****

** **

Trust the math. Encryption is your friend. Use it well, and do your best to*
***

ensure that nothing can compromise it. That's how you can remain secure even
****

in the face of the NSA.****

** **

==========================================****

(F)AIR USE NOTICE: All original content and/or articles and graphics in this
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these copyrighted items are reserved. Articles and graphics have been placed
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