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Zero-Knowledge Proofs

zero-knowledge proofs are one of the most powerful tools cryptographers have ever devised. But unfortunately they’re also relatively poorly understood. In this series of posts I’m going try to give a (mostly) non-mathematical description of what ZK proofs are, and what makes them so special. In this post and the next I’ll talk about some of the ZK protocols we actually use.

2016-09-20: how do you inspect nuclear weapons without learning the secrets of their design? enter zero knowledge proofs.

Mother of the Sea

In 1948, with Tokyo still largely in ruins and the reins of government still in the hands of an occupying army, the nori harvest completely failed. And it kept failing. No one knew why. Years and decades and a world war passed and Kathleen discovered something that no one suspected: Porphyra and another seaweed called Conchocelis rosea weren’t actually 2 different organisms. They were actually 2 different phases of nori’s lifecycle. Conchocelis rosea was a tiny spore-like thing that clung to tiny particles of seashell adrift in the water. The shell fragments were essentially life preservers for the nori-spores, which would otherwise sink to the bottom and be swallowed by the sediments. The nori fishers didn’t know that their harvest was dependent on another harvest, that of the shellfish along the same shores, and the shoals of discarded shells. The nori fishers of Ariake Bay, the producers of over half of Japan’s nori harvest, raised their small shrine to Kathleen. This coming April, they will mark the 51st anniversary of their small festival celebrating a woman that they never met, but whom they call “the mother of the sea.”

Centromeres are tricky

The scientists decided to return to the human genome and search for K111. They isolated DNA from their HIV patients, as well as from healthy people. Remarkably, the scientists didn’t find just 1 copy of K111 in each of their subject’s genomes, as is the case in chimps. The more the scientists looked, the more variants they found. Some K111 viruses were fairly intact, while others were vestiges. The scientists found over 100 copies of the virus in the human genome, scattered across 15 chromosomes.
This finding suggests that between 6 ma and 800 ka ago, K111 was duplicated a few times at a fairly slow pace. It’s possible that Markowitz and his colleagues missed some other copies because the reconstruction of those ancient genomes wasn’t quite accurate enough for their search. But even if we generously assumed that Neanderthals and Denisovans had 20 K111 viruses apiece, that’s still a small fraction of the 100 or more copies of K111 the scientists found in the human genome. It was only later, in the past 800 ka, that K111 started proliferating at a faster pace.

1 reason that K111 has gone overlooked till now is that it found a good place to hide–the center of chromosomes. This region, called the centromere, is a genomic Bermuda Triangle. It’s loaded with lots of short, repetitive stretches of DNA. When scientists reconstruct the sequence of a genome, they break DNA down into many overlapping segments, which they then try to rebuild based on overlapping similarities. Centromere DNA is so similar to itself that it’s easy to line up fragments in many different arrangements. As a result, centromeres make up much of the last 5% of the human genome that has yet to be mapped.

Building Cyborgs

In 2006, DARPA studied cockroaches as a robotics platform. They soon learned that cockroaches have a mind of their own, and will ignore implanted directions (via electrical stimuli) after ~30min. this makes them unsuitable for spy missions, but it triggered interest in the neurobiology community as a new model organism.

Cockroaches have a simple body plan, and have their processing spread around the body. With some basic surgery, a cockroach can be turned into a robot by attaching the antenna to current, you can make a cockroach go left/right

The first workshop for building your own cyborg was this weekend. my specimen didn’t pass final QC because i didn’t secure the antenna cables securely enough, and the cockroach disconnected 😦

Upwards bound

Interstellar had more plot holes than wormholes, but this is still amazing.

What is happening? Suddenly, there’s been a wave of … inspiration! As if in tempo with Christopher Nolan’s INTERSTELLAR, there have also been several short movies that aggressively confront and take down the cynical theme that’s dominated this dismal century (so far). The way so many of YOU have given in to the seductive propaganda of limitations and despair. These wondrous pieces fight back by offering us visions of wondrous possibility.

First… try on this spectacular ode to courage – and our outward spirit – is by Max Shishkin, using the Interstellar score as background, taking us on a tour of vivid SF cinema images of space.
Even better is one of the best things I have ever watched, period. Invest 4 minutes! Scenes all taken (or extrapolated) from reality, not sci fi! This is what being human must be about… or else, why bother?)

Coda: Centuries tend to change direction dramatically, in their 14th year. Could this be our sudden veer? Backing away from the cliffs of cynical despair and getting back on trajectory toward confidence and daring and wonder?

Make it so.