cryptography (7)

'Teleporting' Images...


High-dimensional quantum transport enabled by nonlinear detection. In our concept, information is encoded on a coherent source and overlapped with a single photon from an entangled pair in a nonlinear crystal for up-conversion by sum frequency generation, the latter acting as a nonlinear spatial mode detector. The bright source is necessary to achieve the efficiency required for nonlinear detection. Information and photons flow in opposite directions: one of [the] Bob’s entangled photons is sent to Alice and has no information, while a measurement on the other in coincidence with the upconverted photon establishes the transport of information across the quantum link. Alice need not know this information for the process to work, while the nonlinearity allows the state to be arbitrary and unknown dimension and basis. Credit: Nature Communications (2023). DOI: 10.1038/s41467-023-43949-x

Topics: Applied Physics, Computer Science, Cryptography, Cybersecurity, Quantum Computers, Quantum Mechanics, Quantum Optics

Nature Communications published research by an international team from Wits and ICFO- The Institute of Photonic Sciences, which demonstrates the teleportation-like transport of "patterns" of light—this is the first approach that can transport images across a network without physically sending the image and a crucial step towards realizing a quantum network for high-dimensional entangled states.

Quantum communication over long distances is integral to information security and has been demonstrated with two-dimensional states (qubits) over very long distances between satellites. This may seem enough if we compare it with its classical counterpart, i.e., sending bits that can be encoded in 1s (signal) and 0s (no signal), one at a time.

However, quantum optics allow us to increase the alphabet and to securely describe more complex systems in a single shot, such as a unique fingerprint or a face.

"Traditionally, two communicating parties physically send the information from one to the other, even in the quantum realm," says Prof. Andrew Forbes, the lead PI from Wits University.

"Now, it is possible to teleport information so that it never physically travels across the connection—a 'Star Trek' technology made real." Unfortunately, teleportation has so far only been demonstrated with three-dimensional states (imagine a three-pixel image); therefore, additional entangled photons are needed to reach higher dimensions.

'Teleporting' images across a network securely using only light, Wits University,

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Bitcoin and Gaia...


"What are the environmental impacts of cryptocurrency?" Written by Paul Kim; edited by Jasmine Suarez Mar 17, 2022, 5:21 PM EDT, Business Insider.

 Image: Ethereum, the second biggest cryptocurrency on the market, plans on changing to proof of stake mining in the future. Rachel Mendelson/Insider


Topics: Applied Physics, Computer Science, Cryptography, Economics, Environment, Star Trek, Thermodynamics

In what is now “old school Internet” (or web surfing for fogies), I will get a friend request from someone on Facebook/Meta who is in cryptocurrency. I quote myself in the first paragraph of what I refer to as my “public service announcement):

I am not INTERESTED in crypto. As someone who worked with cryptography as a matter of national security, holding a TS/SCI clearance, when you start your message with “let me explain to YOU how crypto works,” expect to get blocked.

Invariably, I still do, which makes me wonder if they read the PSA or think “they will be the one” to sign me. News flash, pilgrim...I now have another pertinent reason to ignore your blockchain solicitations, actually, several good reasons.

Every time we turn on a light in our homes, there is a thermal budget that we are being charged for (that's how Duke Power makes its money in North Carolina and Perdernales Electric Cooperative in Texas). Bitcoin/Blockchain (I think) caught the imagination because it seemed like a "Federation Credit" from Star Trek, where no one explains fully how a society that is "post-scarcity" somehow feels the need for some type of currency in utopia. It's kind of like magic carpets: you go with the bit for the story - warp drive, Heisenberg compensators, Federation credits. The story, and if you are thoroughly entertained after the denouement, not the physics, is what matters.

You might not be extracting anything from the planet directly, but Bitcoin mining has a massive impact on the planet’s environment.

Mining resources from our planet can take a devastating toll on the environment, both local and global. Even beyond this, using the resource could cause disastrous effects on our planet, and dependence on a single resource can wreak havoc on a country’s economy. Yet, many of these resources are needed for our daily lives -- sometimes as a luxury, sometimes as a necessity. Any responsible country or company should always take pause to consider what impact mining of any kind can have on the planet.

It turns out that these days, one type of mining might be the worst for Earth’s environment: bitcoins. Yes, the “mining” of virtual currency makes its mark on our planet. The unequal distribution of Bitcoin mining across the globe means that some countries are making a much larger dent into the planet’s climate and environment than others ... all for a “resource” that is far from necessary for our society.

Bitcoin mining uses a lot of computing power to solve the cryptographic puzzles that lie at the heart of the industry. As of today (October 30, 2023), each Bitcoin is worth over $34,000, and with the multitude of other cryptocoins out there, using computers to unlock more can be a profitable endeavor. Almost half a trillion dollars of the global economy runs on these “virtual currencies.”

Worst Kind of Mining for the Environment? It Might Be Bitcoin. Erik Klemetti, Discover Magazine


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Zero Days...


Image Source: Tech Target

Topics: Computer Science, Cryptography, Cybersecurity, Spyware

Spyware vendors are exploiting zero days and known vulnerabilities in Android, iOS, and Chrome, sparking an increase in "dangerous hacking tools," warned Google's Threat Analysis Group.

In a blog post on Wednesday, Clement Lecigne, a security engineer at Google, detailed two recent campaigns that TAG discovered to be "both limited and highly targeted." The campaigns leveraged zero-day exploits alongside known vulnerabilities, or N days, against unpatched devices on widely used platforms.

In addition to emphasizing an ongoing patching problem, Google said the threat activity showed just how prevalent spyware vendors have become and the dangers they present, especially when wielding zero days.

"These campaigns are a reminder that the commercial spyware industry continues to thrive," Lecigne wrote in the blog post.

TAG currently tracks more than 30 commercial surveillance vendors that sell exploits or spyware programs to various governments and nation-state threat groups. While Google acknowledged spyware use might be legal under national or international laws, such tools have historically been used against targets such as government officials, journalists, political dissidents, and human rights activists. For example, in 2018, NSO Group's Pegasus spyware was linked to the death of journalist Jamal Khashoggi, who was killed by Saudi government agents in 2018 after being surveilled and tracked via his mobile phone.

While spyware has been used to track high-value targets in the past, Lecigne warned vendors that access to zero days and N days poses an even broader threat.

"Even smaller surveillance vendors have access to 0-days, and vendors stockpiling and using 0-day vulnerabilities in secret pose a severe risk to the internet," Lecigne wrote. "These campaigns may also indicate that exploits and techniques are being shared between surveillance vendors, enabling the proliferation of dangerous hacking tools."

Google: Spyware vendors exploiting iOS, Android zero days, Arielle Waldman, Tech Target News Writer

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QAOA and Privacy…


A quantum computer at IBM’s Thomas J. Watson Research Center.

Credit: Connie Zhou for IBM

Topics: Computer Science, Cryptography, Cybersecurity, Quantum Computer

A team of researchers in China has unveiled a technique that — theoretically — could crack the most commonly used types of digital privacy using a rudimentary quantum computer.

The technique worked in a small-scale demonstration, the researchers report, but other experts are skeptical that the procedure could scale up to beat ordinary computers at the task. Still, they Are quantum computers about to break online privacy. Davide Castelvecchi, Naturewarn that the paper, posted late last month on the arXiv repository1, is a reminder of the vulnerability of online privacy.

Quantum computers are known to be a potential threat to current encryption systems. However, the technology is still in its infancy, and researchers typically estimate that it will be many years until it can be faster than ordinary computers at cracking cryptographic keys.

Researchers realized in the 1990s that quantum computers could exploit peculiarities of physics to perform tasks that seem to be beyond the reach of ‘classical’ computers. Peter Shor, a mathematician now at the Massachusetts Institute of Technology in Cambridge, showed in 19942 how to apply the phenomena of quantum superposition and interference to factoring integer numbers into primes — the integers that cannot be further divided without a remainder.

Are quantum computers about to break online privacy? Davide Castelvecchi, Nature

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City-Sized, Secure Quantum Network...

Physicists Create City-Sized Ultrasecure Quantum Network

Quantum physics experiment has demonstrated an important step toward achieving quantum cryptography among many users, an essential requirement for a secure quantum Internet. Credit: ÖAW and Klaus Pichler Getty Images

Topics: Cryptography, Futurism, Internet of Things, Modern Physics, Quantum Computer, Quantum Mechanics

Quantum cryptography promises a future in which computers communicate with one another over ultrasecure links using the razzle-dazzle of quantum physics. But scaling up the breakthroughs in research labs to networks with a large number of nodes has proved difficult. Now an international team of researchers has built a scalable city-wide quantum network to share keys for encrypting messages.

The network can grow in size without incurring an unreasonable escalation in the costs of expensive quantum hardware. Also, this system does not require any node to be trustworthy, thus removing any security-sapping weak links.

“We have tested it both in the laboratory and in deployed fibers across the city of Bristol” in England, says Siddarth Koduru Joshi of the University of Bristol. He and his colleagues demonstrated their ideas using a quantum network with eight nodes in which the most distant nodes were 17 kilometers apart, as measured by the length of the optical fiber connecting them. The team’s findings appeared in Science Advances on September 2.

Physicists Create City-Sized Ultrasecure Quantum Network, Anil Ananthaswamy, Scientific American

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Quantum Hush...


Party line: the new protocol allows 10 parties to share information securely. (Courtesy: University of Witwatersrand)

Topics: Cryptography, Quantum Computer, Quantum Mechanics

A “quantum secret sharing” scheme that allows 10 parties to share information securely – the highest number so far – has been developed and demonstrated by researchers in South Africa. The protocol involves each party performing quantum operations on the photon without measuring its state and the team says it could help increase both the rate at which data is shared on secure quantum networks and how many parties can be involved in the sharing.

In the original quantum key distribution (QKD) protocol, two parties, known as Alice and Bob, communicate by exchanging photons polarized in one of two possible bases over an untrusted link, each varying the polarization basis of his or her transmitter or receiver randomly. At the end of the transmission, Alice and Bob reveal to each other which basis they used to measure the photons sent and received, but not the result of the measurements.  Alice and Bob then announce their results for a sample of the photons in which they measured in the same polarization basis, to check that the emitted polarization always agrees with the received one. If it does, they can use the remaining photons that they measured in the same basis to form a secure cryptography key that allows them to communicate securely using conventional telecoms technology. A third party that intercepts the photons inevitably disturbs their state, so some of Alice and Bob’s measurements disagree and they know the line is bugged.

‘Quantum secret sharing’ scheme allows 10 parties to communicate securely, Physics World

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Threshold Cryptography...

This artist’s conception of threshold cryptography shows a lock that can only be opened by three people working together. When the threshold cryptosystem receives a request to process information with a secret key, it initially splits the key into shares and sends them to the entire group, each share to a different participant. The three people must agree to work together and also perform their own secret operations on the incoming message. From these actions, each person uses their share key — represented by the three colored circles — to process the message, and then sends the result back to the system. Only the combination of all three partial results can open the lock, reducing the likelihood that a single corrupt party could compromise the system.


Topics: Cryptography, Computer Science, Electrical Engineering, NIST

A new publication by cryptography experts at the National Institute of Standards and Technology (NIST) proposes the direction the technical agency will take to develop a more secure approach to encryption. This approach, called threshold cryptography, could overcome some of the limitations of conventional methods for protecting sensitive transactions and data.

The document, released today in a final version as NIST Roadmap Toward Criteria for Threshold Schemes for Cryptographic Primitives (NISTIR 8214A), offers an outline for developing a new way to implement the cryptographic tools that developers use to secure their systems. Its authors are inviting the cryptography community to collaborate with them on NIST’s budding Threshold Cryptography project, which in part seeks to ensure that threshold implementations are interoperable.

“We are kicking the threshold cryptography development effort into high gear,” said Apostol Vassilev, a NIST computer scientist. “Over the coming months, the Threshold Cryptography project will be engaging with the public to define criteria for this work. We want to get feedback from the community so we can consider a variety of threshold schemes and standardization paths.”

Threshold cryptography takes its name from the idea that individual keyholders cannot open a lock on their own, as is common in conventional cryptography. Instead, out of a group of keyholders, there must be a minimum number of them — a “threshold” number — working together to open the lock. In practice, this lock is an electronic cryptosystem that protects confidential information, such as a bank account number or an authorization to transfer money from that account.

NIST Kick-Starts ‘Threshold Cryptography’ Development Effort

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