2,661 research outputs found
Is Ethereum\u27s ProgPoW ASIC Resistant?
Cryptocurrencies are more than a decade old and several issues have been discovered since their then. One of these issues is a partial negation of the intent to “democratize” money by decentralizing control of the infrastructure that creates, transmits, and stores monetary data. The Programmatic Proof of Work (ProgPoW) algorithm is intended as a possible solution to this problem for the Ethereum cryptocurrency. This paper examines ProgPow’s claim to be Application Specific Integrated Circuit (ASIC) resistant. This is achieved by isolating the proof-of-work code from the Ethereum blockchain, inserting the ProgPoW algorithm, and measuring the performance of the new implementation as a multithread CPU program, as well as a GPU implementation. The most remarkable difference between the ProgPoW algorithm and the currently implemented Ethereum Proof-of Work is the addition of a random sequence of math operations in the main loop that require increased memory bandwidth. Analyzing and comparing the performance of the CPU and GPU implementations should provide an insight into how the ProgPoW algorithm might perform on an ASIC
Foundations, Properties, and Security Applications of Puzzles: A Survey
Cryptographic algorithms have been used not only to create robust ciphertexts
but also to generate cryptograms that, contrary to the classic goal of
cryptography, are meant to be broken. These cryptograms, generally called
puzzles, require the use of a certain amount of resources to be solved, hence
introducing a cost that is often regarded as a time delay---though it could
involve other metrics as well, such as bandwidth. These powerful features have
made puzzles the core of many security protocols, acquiring increasing
importance in the IT security landscape. The concept of a puzzle has
subsequently been extended to other types of schemes that do not use
cryptographic functions, such as CAPTCHAs, which are used to discriminate
humans from machines. Overall, puzzles have experienced a renewed interest with
the advent of Bitcoin, which uses a CPU-intensive puzzle as proof of work. In
this paper, we provide a comprehensive study of the most important puzzle
construction schemes available in the literature, categorizing them according
to several attributes, such as resource type, verification type, and
applications. We have redefined the term puzzle by collecting and integrating
the scattered notions used in different works, to cover all the existing
applications. Moreover, we provide an overview of the possible applications,
identifying key requirements and different design approaches. Finally, we
highlight the features and limitations of each approach, providing a useful
guide for the future development of new puzzle schemes.Comment: This article has been accepted for publication in ACM Computing
Survey
JaxNet: Scalable Blockchain Network
Today's world is organized based on merit and value. A single global currency
that's decentralized is needed for a global economy. Bitcoin is a partial
solution to this need, however it suffers from scalability problems which
prevent it from being mass-adopted. Also, the deflationary nature of bitcoin
motivates people to hoard and speculate on them instead of using them for day
to day transactions. We propose a scalable, decentralized cryptocurrency that
is based on Proof of Work.The solution involves having parallel chains in a
closed network using a mechanism which rewards miners proportional to their
effort in maintaining the network.The proposed design introduces a novel
approach for solving scalability problem in blockchain network based on merged
mining.Comment: 55 pages. 10 figure
Soft Gamma-ray Detector for the ASTRO-H Mission
ASTRO-H is the next generation JAXA X-ray satellite, intended to carry
instruments with broad energy coverage and exquisite energy resolution. The
Soft Gamma-ray Detector (SGD) is one of ASTRO-H instruments and will feature
wide energy band (40-600 keV) at a background level 10 times better than the
current instruments on orbit. SGD is complimentary to ASTRO-H's Hard X-ray
Imager covering the energy range of 5-80 keV. The SGD achieves low background
by combining a Compton camera scheme with a narrow field-of-view active shield
where Compton kinematics is utilized to reject backgrounds. The Compton camera
in the SGD is realized as a hybrid semiconductor detector system which consists
of silicon and CdTe (cadmium telluride) sensors. Good energy resolution is
afforded by semiconductor sensors, and it results in good background rejection
capability due to better constraints on Compton kinematics. Utilization of
Compton kinematics also makes the SGD sensitive to the gamma-ray polarization,
opening up a new window to study properties of gamma-ray emission processes.
The ASTRO-H mission is approved by ISAS/JAXA to proceed to a detailed design
phase with an expected launch in 2014. In this paper, we present science
drivers and concept of the SGD instrument followed by detailed description of
the instrument and expected performance.Comment: 17 pages, 15 figures, Proceedings of the SPIE Astronomical
Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to
Gamma Ray
From FPGA to ASIC: A RISC-V processor experience
This work document a correct design flow using these tools in the Lagarto RISC- V Processor and the RTL design considerations that must be taken into account, to move from a design for FPGA to design for ASIC
HashCore: Proof-of-Work Functions for General Purpose Processors
Over the past five years, the rewards associated with mining Proof-of-Work
blockchains have increased substantially. As a result, miners are heavily
incentivized to design and utilize Application Specific Integrated Circuits
(ASICs) that can compute hashes far more efficiently than existing general
purpose hardware. Currently, it is difficult for most users to purchase and
operate ASICs due to pricing and availability constraints, resulting in a
relatively small number of miners with respect to total user base for most
popular cryptocurrencies. In this work, we aim to invert the problem of ASIC
development by constructing a Proof-of-Work function for which an existing
general purpose processor (GPP, such as an x86 IC) is already an optimized
ASIC. In doing so, we will ensure that any would-be miner either already owns
an ASIC for the Proof-of-Work system they wish to participate in or can attain
one at a competitive price with relative ease. In order to achieve this, we
present HashCore, a Proof-of-Work function composed of "widgets" generated
pseudo-randomly at runtime that each execute a sequence of general purpose
processor instructions designed to stress the computational resources of such a
GPP. The widgets will be modeled after workloads that GPPs have been optimized
for, for example, the SPEC CPU 2017 benchmark suite for x86 ICs, in a technique
we refer to as inverted benchmarking. We provide a proof that HashCore is
collision-resistant regardless of how the widgets are implemented. We observe
that GPP designers/developers essentially create an ASIC for benchmarks such as
SPEC CPU 2017. By modeling HashCore after such benchmarks, we create a
Proof-of-Work function that can be run most efficiently on a GPP, resulting in
a more accessible, competitive, and balanced mining market
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