Understanding Remailers (and lifehacking: grounding)

As most of you have figured out, I’m not a huge fan of encryption. This is because you should only trust things you understand, and thoroughly understanding encryption takes a lot of time and study.

However, it’s still worthwhile to learn a bit about it. The concepts are often applicable to more mundane situations, and can even help you spot otherwise not-so-obvious implications of real-world security decisions.

The linked summaries of anonymous remailers are a decent case in point. I find it particularly interesting to see the differences between the Mixmaster and Mixminon systems. (The first was written by Cottrell and maintained by Sassaman until the latters’ suicide in 2011. The second was written by Mathewson based on research with Danezis and Dingledine and is not actively maintained.)

Lifehacking / Grounding update:
While I’m not sure exactly why the ground + reflector setup* appears to give me more energy and strengthen my immune system, tests suggest that the effect may be connected with electrical energy above several hundred kiloherz, maybe much higher.

* (Skin connection to house ground. 2×0.5m foil reflector backed by wood plank 10cm overhead, foil side down)

Here’s why.

After considerable experimentation suggested that my ground + reflector setup was indeed having a substantial effect, I started noticing a new form of sleep disturbance. Analyzing the electromyogram data showed a new source of continuous noise present in the recordings, beginning some time prior to the sleep disturbance.

I added a simple RF choke to see what would happen. The choke eliminated the new type of sleep disturbance initially, but it eventually came back even with the choke in place. However, I noticed that the choke entirely eliminated the “more energy” and possible health benefits of the ground + reflector connection in one orientation — with the choke right at the ground connection. With ~0.25m of wire and the choke a similar distance from my body, I noticed no reduction in the beneficial effects.

The consisted of 9 turns around an Amidon FT140-77 ferrite toroid, for a measured inductance of 110uH. The core was wound so that it was directly after the alligator clip on a standard alligator clip lead.

Unfortunately, without knowing the capacitances involved (not so easy to figure out, since it’s a question of body capacitance + capacitance in the walls, I think) it’s hard to say exactly where the low-pass filter rolloff starts. Still, I’m guessing it’s > 100kHz.


“A remailer is slang for a system that allows you to send anonymous email to a recipient. It re-mails messages for you. There are a lot of reasons why people would want to send anonymous emails.

Researchers and Survey Participants, who don’t want to expose their opinions on sensitive topics like religion or politics
Whistleblowers, who want to report illegal activity of a coworker, government or company – but can’t risk losing their job or being prosecuted
Journalists, who want to correspond with a source without exposing the source, or being tracked down themselves.
Law Enforcement, who want to communicate with confidential sources or undercover agents without risking their operational security
Activists, protesting against repressive regimes like the ones we’ve seen in the Middle East Consumers, who want to send feedback on a product or service Individuals who don’t trust their Internet Service Provider or Network Admin

In a series of blog posts, we’re going to look at the theory and implementation of different remailing systems. We’ll assume you’re familiar with some basics of cryptography – symmetric (secret-key) and asymmetric (public key) cryptography for the most part – and with the general idea of how Tor works. If you don’t know these things, you’ll probably be able to follow along well enough, but may miss some of the comparisons.”

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