Monday, January 30, 2017


World Associated Press

Recent developments surrounding the South China Sea

HRVOJE HRANJSKI,Associated Press 13 hours ago 

Sunday, January 29, 2017

GettyImages-580504057

Google’s neural networks invent their own encryption

Machines have been learning how to send secret messages to each other.
John Lund/Getty
Computers are keeping secrets. A team from Google Brain, Google’s deep learning project, has shown that machines can learn how to protect their messages from prying eyes.
Researchers Martín Abadi and David Andersen demonstrate that neural networks, or “neural nets” – computing systems that are loosely based on artificial neurons – can work out how to use a simple encryption technique.
In their experiment, computers were able to make their own form of encryption using machine learning, without being taught specific cryptographic algorithms. The encryption was very basic, especially compared to our current human-designed systems. Even so, it is still an interesting step for neural nets, which the authors state “are generally not meant to be great at cryptography”.

Meet Mustafa Suleyman, co-founder of DeepMind – part of Google’s artificial intelligence family – at the Reinventing Energy Summit

The Google Brain team started with three neural nets called Alice, Bob and Eve. Each system was trained to perfect its own role in the communication. Alice’s job was to send a secret message to Bob, Bob’s job was to decode the message that Alice sent, and Eve’s job was to attempt to eavesdrop.
To make sure the message remained secret, Alice had to convert her original plain-text message into complete gobbledygook, so that anyone who intercepted it (like Eve) wouldn’t be able to understand it. The gobbledygook – or “cipher text” – had to be decipherable by Bob, but nobody else. Both Alice and Bob started with a pre-agreed set of numbers called a key, which Eve didn’t have access to, to help encrypt and decrypt the message.

Practice makes perfect

Initially, the neural nets were fairly poor at sending secret messages. But as they got more practice, Alice slowly developed her own encryption strategy, and Bob worked out how to decrypt it.
After the scenario had been played out 15,000 times, Bob was able to convert Alice’s cipher text message back into plain text, while Eve could guess just 8 of the 16 bits forming the message. As each bit was just a 1 or a 0, that is the same success rate you would expect from pure chance. The research is published on arXiv.
We don’t know exactly how the encryption method works, as machine learning provides a solution but not an easy way to understand how it is reached. In practice, this also means that it is hard to give any security guarantees for an encryption method created in this way, so the practical implications for the technology could be limited.
“Computing with neural nets on this scale has only become possible in the last few years, so we really are at the beginning of what’s possible,” says Joe Sturonas of encryption company PKWARE in Milwaukee, Wisconsin.
Computers have a very long way to go if they’re to get anywhere near the sophistication of human-made encryption methods. They are, however, only just starting to try.
Journal reference: arxiv.org/abs/1610.06918
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Saturday, January 28, 2017


Japanese spacecraft spots planet-spanning wave on Venus


In these images from Japan’s Akatsuki spacecraft, a stationary bow wave is seen on Venus over several days in December 2015. Credit: JAXA

Images from Japan’s Akatsuki spacecraft have revealed a gigantic wave in the atmosphere of Venus, and scientists say it may be the largest such feature in the solar system.
The bow-shaped wave ran north-south for 6,000 miles (10,000 kilometers) and stayed stationary for at least four days in December 2015. That is surprising, scientists said, because Venus’s thick sulfuric acid clouds move with a jet stream at more than 220 mph (360 kilometers per hour).
It turns out the atmospheric wave was positioned over Aphrodite Terra, a vast highland region the size of Africa.
While Venus’s “super-rotating” winds whip clouds around the globe at altitudes near 40 miles (65 kilometers), the planet spins slowly, taking 243 Earth days to complete one rotation. On Venus, a day is longer than a year.
“Over several days of observation, the bow-shaped structure remained relatively fixed in position above the highland on the slowly rotating surface, despite the background atmospheric super rotation,” scientists wrote in their report. “We suggest that the bow-shaped structure is the result of an atmospheric gravity wave generated in the lower atmosphere by mountain topography that then propagated upwards.”
The Japanese research team reported their findings Jan. 16 in a paper published in the journal Nature Geoscience.
Gravity waves form when a fluid, such as water, plasma or a gas, becomes disturbed. A mountain or island can generate a gravity wave in Earth’s atmosphere when air blows over the obstacle, but the wave on Venus was much larger than any seen on Earth.
Akatsuki’s orbit prevented the spacecraft from watching the wave for about a month after its initial discovery. By mid-January of last year, when the Aphrodite Terra region was again observable from Akatsuki, the wave had disappeared.
The scientists wrote that such a large gravity wave created by highlands on Venus is “difficult to reconcile” with supposed conditions deeper in the planet’s atmosphere near its scorching surface. Researchers suggest the winds in the lower atmosphere of Venus, believed to be much lighter than the winds higher up, may be more variable than previously thought.
The Japan Aerospace Exploration Agency’s Akatsuki spacecraft entered orbit around Venus a few days before the probe’s infrared and ultraviolet cameras spotted the bow wave.
Akatsuki was originally scheduled to start its mission at Venus in December 2010, but a propulsion system problem kept the spacecraft from completing a rocket burn to enter orbit. Five years later, the Japanese-built probe was back in the vicinity of Venus for a second chance.
The maneuver worked, and Akatsuki officially kicked off its science mission last year, and is now the only spacecraft operating around Venus.
Email the author.
Follow Stephen Clark on Twitter: @StephenClark1.

Tuesday, December 20, 2016

World

Japan's Top Court Deals Blow to Opponents of US Base on Okinawa

VOA News 7 hours ago