NSA surveillance: A guide to staying secure – Schneier
Dragnet Network surveillance:
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.
RULE 1: Force the NSA to attack you personally
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.
RULE 2: Monitor for leakage of Meta data
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.
RULE 3: Place Encryption directly onto ROUTERS.
Eg Run OpenVPN from your ROUTER, to encrypt all devices connecting to it.
RULE 4: Treat your Router and the ISP as enemy territory.
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.
RULE 5: Encrypt routers and devices with long passwords – say 20 characters or more. Use full stops and brackets.
Open Source Products:
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.
RULE 6: Use Open Source rather than propriety software. Do not trust any keys or software written or approved by the NSA as a precautionary measure.
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.”
RULE 7: Double whatever encryption standard you intended to use. Test your systems to find the HIGHEST possible encryption that will work on the hardware.
Secure your end laptops:
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.
RULE 8: Secure your laptop. Don’t travel through customs without expecting them to demand your passwords. Use fake dual passwords for the duration of travel. Send your real data via usb pen via DHL or the post… encrypted of course. Don’t take it on your laptop.
Schneier’s 5 guidelines:
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.