Category Archives: Cryptography

European Researchers Reveal The Physics Of The Secret

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March 27, 2014

[ Watch the Video: Keeping Secrets in a World of Spies and Mistrust ]

Peter Suciu for redOrbit.com Your Universe Online

Is it really a secret if researchers share it? In the March 27 issue of Nature, the weekly international journal of science, researchers Artur Ekert and Renato Renner revealed what physics can tell us about keeping our secrets secret.

This comes after high profile revelation that the National Security Agency (NSA) had been spying on emails, phone calls and other means of communications. Numerous companies have denied allegations of assisting the NSA, but a report from January suggested spy agencies might not just be listening in on phone calls or monitoring Internet browsing. Radio waves are also a secret technology being monitored by the NSA, redOrbit reported back in January.

Is nothing safe?

In the paper, titled The Ultimate Physical Limits of Privacy, the authors noted:

Among those who make a living from the science of secrecy, worry and paranoia are just signs of professionalism. Can we protect our secrets against those who wield superior technological powers? Can we trust those who provide us with tools for protection? Can we even trust ourselves, our own freedom of choice? Recent developments in quantum cryptography show that some of these questions can be addressed and discussed in precise and operational terms, suggesting that privacy is indeed possible under surprisingly weak assumptions.

Ekert, who is the director of the Centre for Quantum Technlogy, professor of quantum physics at the University of Oxford, UK, suggested in a statement, Recent developments in quantum cryptography show that privacy is possible under stunningly weak assumptions about the freedom of action we have and the trustworthiness of the devices we use.

Ekert is also a Lee Kong Chian Centennial Professor at the National University of Singapore.

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European Researchers Reveal The Physics Of The Secret

Keeping secrets in a world of spies and mistrust

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Revelations of the extent of government surveillance have thrown a spotlight on the security -- or lack thereof -- of our digital communications. Even today's encrypted data is vulnerable to technological progress. What privacy is ultimately possible? In the 27 March issue of Nature, the weekly international journal of science, researchers Artur Ekert and Renato Renner review what physics tells us about keeping our secrets secret.

In the history of secret communication, the most brilliant efforts of code-makers have been matched time and again by the ingenuity of code-breakers. Sometimes we can even see it coming. We already know that one of today's most widely used encryption systems, RSA, will become insecure once a quantum computer is built.

But that story need not go on forever. "Recent developments in quantum cryptography show that privacy is possible under stunningly weak assumptions about the freedom of action we have and the trustworthiness of the devices we use," says Ekert, Professor of Quantum Physics at the University of Oxford, UK, and Director of the Centre for Quantum Technologies at the National University of Singapore. He is also the Lee Kong Chian Centennial Professor at the National University of Singapore.

Over 20 years ago, Ekert and others independently proposed a way to use the quantum properties of particles of light to share a secret key for secure communication. The key is a random sequence of 1s and 0s, derived by making random choices about how to measure the particles (and some other steps), that is used to encrypt the message. In the Nature Perspective, he and Renner describe how quantum cryptography has since progressed to commercial prospect and into new theoretical territory.

Even though privacy is about randomness and trust, the most surprising recent finding is that we can communicate secretly even if we have very little trust in our cryptographic devices -- imagine that you buy them from your enemy -- and in our own abilities to make free choices -- imagine that your enemy is also manipulating you. Given access to certain types of correlations, be they of quantum origin or otherwise, and having a little bit of free will, we can protect ourselves. What's more, we can even protect ourselves against adversaries with superior technology that is unknown to us.

"As long as some of our choices are not completely predictable and therefore beyond the powers that be, we can keep our secrets secret," says Renner, Professor of Theoretical Physics at ETH Zurich, Switzerland. This arises from a mathematical discovery by Renner and his collaborator about 'randomness amplification': they found that a quantum trick can turn some types of slightly-random numbers into completely random numbers. Applied in cryptography, such methods can reinstate our abilities to make perfectly random choices and guarantee security even if we are partially manipulated.

"As well as there being exciting scientific developments in the past few years, the topic of cryptography has very much come out of the shadows. It's not just spooks talking about this stuff now," says Ekert, who has worked with and advised several companies and government agencies.

The semi-popular essay cites 68 works, from the writings of Edgar Allen Poe on cryptography in 1841, through the founding papers of quantum cryptography in 1984 and 1991, right up to a slew of results from 2013.

The authors conclude that "The days we stop worrying about untrustworthy or incompetent providers of cryptographic services may not be that far away."

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Keeping secrets in a world of spies and mistrust

Quantum cryptography: Keeping your secrets secret

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19 hours ago Credit: WinBeta

An article in Nature reviewing developments in quantum cryptography describes how we can keep our secrets secret even when faced with the double challenge of mistrust and manipulation.

Revelations of the extent of government surveillance have thrown a spotlight on the security or lack thereof of our digital communications. Even today's encrypted data is vulnerable to technological progress. What privacy is ultimately possible? In the 27 March issue of Nature, researchers Artur Ekert and Renato Renner review what physics tells us about keeping our secrets secret.

In the history of secret communication, the most brilliant efforts of code-makers have been matched time and again by the ingenuity of code-breakers. Sometimes we can even see it coming. We already know that one of today's most widely used encryption systems, RSA, will become insecure once a quantum computer is built.

But that story need not go on forever. "Recent developments in quantum cryptography show that privacy is possible under stunningly weak assumptions about the freedom of action we have and the trustworthiness of the devices we use," says Ekert, Professor of Quantum Physics at the University of Oxford, UK, and Director of the Centre for Quantum Technologies at the National University of Singapore. He is also the Lee Kong Chian Centennial Professor at the National University of Singapore.

Over 20 years ago, Ekert and others independently proposed a way to use the quantum properties of particles of light to share a secret key for secure communication. The key is a random sequence of 1s and 0s, derived by making random choices about how to measure the particles (and some other steps), that is used to encrypt the message. In the Nature Perspective, he and Renner describe how quantum cryptography has since progressed to commercial prospect and into new theoretical territory.

This video is not supported by your browser at this time.

Even though privacy is about randomness and trust, the most surprising recent finding is that we can communicate secretly even if we have very little trust in our cryptographic devices imagine that you buy them from your enemy and in our own abilities to make free choices imagine that your enemy is also manipulating you. Given access to certain types of correlations, be they of quantum origin or otherwise, and having a little bit of free will, we can protect ourselves. What's more, we can even protect ourselves against adversaries with superior technology that is unknown to us.

"As long as some of our choices are not completely predictable and therefore beyond the powers that be, we can keep our secrets secret," says Renner, Professor of Theoretical Physics at ETH Zurich, Switzerland. This arises from a mathematical discovery by Renner and his collaborator about 'randomness amplification': they found that a quantum trick can turn some types of slightly-random numbers into completely random numbers. Applied in cryptography, such methods can reinstate our abilities to make perfectly random choices and guarantee security even if we are partially manipulated.

"As well as there being exciting scientific developments in the past few years, the topic of cryptography has very much come out of the shadows. It's not just spooks talking about this stuff now," says Ekert, who has worked with and advised several companies and government agencies.

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Quantum cryptography: Keeping your secrets secret

Who Is Satoshi Nakamoto, Mysterious Bitcoin Founder?

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The Short Answer

No one knows. Not conclusively, at any rate. Satoshi Nakamoto is the potentially pseudonymous name associated with the person or group of people who released the original Bitcoin white paper in 2008 and worked on the original Bitcoin software that was released in 2009. Since Satoshi's identity is tied up intricately with Bitcoin's history, it is helpful to understand Bitcoin's provenance. Bitcoin is one of the first digital currencies which use peer-to-peer technology to facilitate instant payments.

Time Line of Early Bitcoin Events

Aug. 18, 2008: The domain name bitcoin.org is registered. Today, at least, this domain is "WhoisGuard Protected," meaning the identity of the person who registered it is not public information.

Oct. 31, 2008: Someone using the name Satoshi Nakamoto makes an announcement on The Cryptography Mailing list at metzdowd.com: "I've been working on a new electronic cash system that's fully peer-to-peer, with no trusted third party. The paper is available at http://www.bitcoin.org/bitcoin.pdf." This link leads to the infamous white paper published on bitcoin.org entitled "Bitcoin: A Peer-to-Peer Electronic Cash System." This paper would become the Magna Carta for how Bitcoin operates today.

Jan. 3, 2009: The first Bitcoin block is mined, i.e. Block 0. This is also known as the "genesis block" and contains the text: "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks," perhaps as proof that the block was mined on or after that date, and perhaps also as relevant political commentary.

Jan. 8, 2009: The first version of the Bitcoin software is announced on The Cryptography Mailing list.

Jan. 9, 2009: Block 1 is mined, and Bitcoin mining commences in earnest.

Before Satoshi

Though it is tempting to believe the media's spin that Satoshi Nakamoto is a lone, quixotic genius who created Bitcoin out of thin air, history has taught us that such innovations do not happen in a vacuum. All major scientific discoveries, no matter how original-seeming, were built on previously existing research. Isaac Newton had been working toward a treatise on calculus, but fellow mathematician Gottfried Wilhelm Leibniz published first, resulting eventually in controversy over who should be credited as the inventor of calculus.

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Who Is Satoshi Nakamoto, Mysterious Bitcoin Founder?

Academics Spy Weaknesses in Bitcoin’s Foundations

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Game theory suggests the rules governing Bitcoin may need to be updated if the currency is to endure.

One thing cannot be disputed about the person (or persons) responsible for creating Bitcoin: they were skilled in math, and expert at coding. Five years after the Bitcoin software was first released, no major fixes have been needed to the core code, which uses cryptography to generate and transfer virtual money.

Yet signs are emerging of more subtle flaws in the vision of Satoshi Nakamoto (which may or may not be a pseudonym), with analysis suggesting the rules governing how Bitcoin operates as a currency may be far from perfect. Some researchers claim that these rules leave room for cheats to destabilize Bitcoin. Others have concluded that major changes to the currencys rules will be needed as the number of bitcoins in circulation increases.

In the real world, people dont always follow the rulesthey do whats best for them, says Joshua Kroll, a researcher at Princeton. Understanding this is the key to understanding whether and how Bitcoin survivesit tells you whether the system can last for a long time, [and] how robust is it in the face of shocks.

Kroll and others are exploring possible problems using game theory, a way to mathematically calculate how individuals might choose to coperate, compete, or cheat given the options available to them and the strategies of others.

One conclusion drawn by Kroll and his Princeton colleagues Ian Davey and Ed Felten is that those rules will have to be significantly changed if Bitcoin is to last. Their models predict that interest in mining for bitcoins, by downloading and running the Bitcoin software, will drop off as the number in circulation grows toward the cap of 21 million set by Nakamoto. This would be a problem because computers running the mining software also maintain the ledger of transactions, known as the blockchain, that records and guarantees bitcoin transactions (see What Bitcoin Is and Why It Matters).

Miners earn newly minted bitcoins for adding new sections to the blockchain. But the amount awarded for adding a section is periodically halved so that the total number of bitcoins in circulation never exceeds 21 million (the reward last halved in 2012 and is set to do so again in 2016). Transaction fees paid to miners for helping verify transfers are supposed to make up for that loss of income. But fees are currently negligible, and the Princeton analysis predicts that under the existing rules these fees wont become significant enough to make mining worth doing in the absence of freshly minted bitcoins.

The only solution Kroll sees is to rewrite the rules of the currency. It would need some kind of governance structure that agreed to have a kind of tax on transactions or not to limit the number of bitcoins created, he says. We expect both mechanisms to come into play.

That kind of approach is common in established economies, which tame things like insider trading with laws and regulatory agencies and have central banks to shape economies. But many backers of Bitcoin prize the way it currently operates without centralized control, and would likely rebel at any suggestion of changing the rules.

Researchers from Cornell claim to have found another problem with bitcoin mining. At the Financial Cryptography conference this month, they presented work suggesting that so-called selfish miners could exploit the current rules to gain more than a fair reward for their work.

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Academics Spy Weaknesses in Bitcoin’s Foundations