This document discusses efficient implementation of cryptographic pairings. It begins by introducing pairings and their properties like bilinearity. It describes the hard computational problems that pairings are based on and how suitable elliptic curves and algorithms like the Tate pairing can be used to implement pairings securely. The document then discusses optimizations to the basic Tate pairing algorithm as well as other pairing-friendly curves and pairings like the Ate pairing. It also covers efficient arithmetic in extension fields and techniques for fast final exponentiation.
This document discusses the four Fourier representations used to represent signals: Fourier series, discrete-time Fourier series, Fourier transform, and discrete-time Fourier transform. It explains why the frequencies of the sinusoids used in the representations are discrete or continuous depending on whether the signal is periodic or non-periodic. It also discusses why the integration/summation intervals and normalization factors differ between the four representations.
1) The document presents a spectral sum rule for conformal field theories relating a weighted integral of the spectral density to one-point functions of the stress tensor operator.
2) It regularizes the retarded Green's function to remove divergent pieces, arriving at a difference of spectral densities that is analytic and well-behaved.
3) The sum rule constrains the parameters of the three-point function of the stress tensor in terms of the one-point function, and is checked against holographic calculations in anti-de Sitter space.
This document discusses how the Traveling Salesman Problem (TSP) is NP-Complete. It first shows that TSP is in NP by describing a nondeterministic polynomial time algorithm to solve it. It then reduces the known NP-Complete Hamiltonian Cycle problem to TSP by constructing an equivalent instance of TSP from any Hamiltonian Cycle problem instance in polynomial time, showing that Hamiltonian Cycle is polynomial time reducible to TSP. Therefore, since any problem in NP can be reduced to Hamiltonian Cycle and Hamiltonian Cycle can be reduced to TSP, any problem in NP can be reduced to TSP, proving that TSP is NP-Complete.
Some Properties of Determinant of Trapezoidal Fuzzy Number MatricesIJMERJOURNAL
ABSTRACT: The fuzzy set theory has been applied in many fields such as management, engineering, matrices and so on. In this paper, some elementary operations on proposed trapezoidal fuzzy numbers (TrFNs) are defined. We also defined some operations on trapezoidal fuzzy matrices (TrFMs). The notion of Determinant of trapezoidal fuzzy matrices are introduced and discussed. Some of their relevant properties have also been verified.
A note on arithmetic progressions in sets of integersLukas Nabergall
This document presents a new upper bound on r3(n), the maximum size of a set of integers between 1 and n that contains no three elements in arithmetic progression. The author proves that r3(n) = O(n/log^h n) for any arbitrarily large h, improving on previous bounds. The proof uses the fundamental theorem of discrete calculus and the pigeonhole principle to show that any sufficiently dense set of integers must contain arbitrarily long arithmetic progressions. This verifies a 1936 conjecture of Erdos and improves understanding of a major problem in combinatorics.
This document discusses reductions in complexity theory. It begins with definitions of reductions, completeness, and hardness. It then provides examples of NP-complete problems like SAT and 3SAT. The document shows reductions between problems like SAT ≤p 3SAT and Hamiltonian Circuit ≤p TSP. It explains the Cook-Levin theorem that SAT is NP-complete. Overall, the document introduces reductions and uses examples to illustrate how reductions can be used to prove completeness results.
A Commutative Alternative to Fractional Calculus on k-Differentiable FunctionsMatt Parker
This document presents a method for creating a commutative operator that acts parallel to fractional calculus operators on continuous functions. It defines spaces Ck that contain images of continuous functions and combines these into a space Cdiff that contains a subset isomorphic to the space of continuous functions C(R). An operator Dk is defined on Cdiff that commutes with itself and acts equivalently to fractional derivatives on C(R) up to the differentiability of the function. This provides a commutative alternative to fractional calculus on continuous functions.
This document summarizes the derivation of an evidence lower bound (ELBO) for latent LSTM allocation, a model that uses an LSTM to determine topic assignments in a topic modeling framework. It expresses the ELBO as terms related to the variational posterior distributions over topics and topics proportions, the generative process of words given topics, and the LSTM's prediction of topic assignments. It also describes how to optimize the ELBO with respect to the variational and LSTM parameters through gradient ascent.
This document discusses the four Fourier representations used to represent signals: Fourier series, discrete-time Fourier series, Fourier transform, and discrete-time Fourier transform. It explains why the frequencies of the sinusoids used in the representations are discrete or continuous depending on whether the signal is periodic or non-periodic. It also discusses why the integration/summation intervals and normalization factors differ between the four representations.
1) The document presents a spectral sum rule for conformal field theories relating a weighted integral of the spectral density to one-point functions of the stress tensor operator.
2) It regularizes the retarded Green's function to remove divergent pieces, arriving at a difference of spectral densities that is analytic and well-behaved.
3) The sum rule constrains the parameters of the three-point function of the stress tensor in terms of the one-point function, and is checked against holographic calculations in anti-de Sitter space.
This document discusses how the Traveling Salesman Problem (TSP) is NP-Complete. It first shows that TSP is in NP by describing a nondeterministic polynomial time algorithm to solve it. It then reduces the known NP-Complete Hamiltonian Cycle problem to TSP by constructing an equivalent instance of TSP from any Hamiltonian Cycle problem instance in polynomial time, showing that Hamiltonian Cycle is polynomial time reducible to TSP. Therefore, since any problem in NP can be reduced to Hamiltonian Cycle and Hamiltonian Cycle can be reduced to TSP, any problem in NP can be reduced to TSP, proving that TSP is NP-Complete.
Some Properties of Determinant of Trapezoidal Fuzzy Number MatricesIJMERJOURNAL
ABSTRACT: The fuzzy set theory has been applied in many fields such as management, engineering, matrices and so on. In this paper, some elementary operations on proposed trapezoidal fuzzy numbers (TrFNs) are defined. We also defined some operations on trapezoidal fuzzy matrices (TrFMs). The notion of Determinant of trapezoidal fuzzy matrices are introduced and discussed. Some of their relevant properties have also been verified.
A note on arithmetic progressions in sets of integersLukas Nabergall
This document presents a new upper bound on r3(n), the maximum size of a set of integers between 1 and n that contains no three elements in arithmetic progression. The author proves that r3(n) = O(n/log^h n) for any arbitrarily large h, improving on previous bounds. The proof uses the fundamental theorem of discrete calculus and the pigeonhole principle to show that any sufficiently dense set of integers must contain arbitrarily long arithmetic progressions. This verifies a 1936 conjecture of Erdos and improves understanding of a major problem in combinatorics.
This document discusses reductions in complexity theory. It begins with definitions of reductions, completeness, and hardness. It then provides examples of NP-complete problems like SAT and 3SAT. The document shows reductions between problems like SAT ≤p 3SAT and Hamiltonian Circuit ≤p TSP. It explains the Cook-Levin theorem that SAT is NP-complete. Overall, the document introduces reductions and uses examples to illustrate how reductions can be used to prove completeness results.
A Commutative Alternative to Fractional Calculus on k-Differentiable FunctionsMatt Parker
This document presents a method for creating a commutative operator that acts parallel to fractional calculus operators on continuous functions. It defines spaces Ck that contain images of continuous functions and combines these into a space Cdiff that contains a subset isomorphic to the space of continuous functions C(R). An operator Dk is defined on Cdiff that commutes with itself and acts equivalently to fractional derivatives on C(R) up to the differentiability of the function. This provides a commutative alternative to fractional calculus on continuous functions.
This document summarizes the derivation of an evidence lower bound (ELBO) for latent LSTM allocation, a model that uses an LSTM to determine topic assignments in a topic modeling framework. It expresses the ELBO as terms related to the variational posterior distributions over topics and topics proportions, the generative process of words given topics, and the LSTM's prediction of topic assignments. It also describes how to optimize the ELBO with respect to the variational and LSTM parameters through gradient ascent.
The document discusses the theory of NP-completeness. It begins by classifying problems as solvable, unsolvable, tractable, or intractable. It then defines deterministic and nondeterministic algorithms, and how nondeterministic algorithms can be expressed. The document introduces the complexity classes P and NP. It discusses reducing one problem to another to prove NP-completeness via transitivity. Several classic NP-complete problems are proven to be NP-complete, such as 3SAT, 3-coloring, and subset sum. The document also discusses how to cope with NP-complete problems in practice by sacrificing optimality, generality, or efficiency.
no U-turn sampler, a discussion of Hoffman & Gelman NUTS algorithmChristian Robert
The document describes the No-U-Turn Sampler (NUTS), an extension of Hamiltonian Monte Carlo (HMC) that aims to avoid the random walk behavior and poor mixing that can occur when the trajectory length L is not set appropriately. NUTS augments the model with a slice variable and uses a deterministic procedure to select a set of candidate states C based on the instantaneous distance gain, avoiding the need to manually tune L. It builds up a set of possible states B by doubling a binary tree and checking the distance criterion on subtrees, then samples from the uniform distribution over C to generate proposals. This allows NUTS to automatically determine an appropriate trajectory length and avoid issues like periodicity that can plague
TopicRNN is a generative model for documents that:
1. Draws a topic vector from a standard normal distribution and uses it to generate words in a document.
2. Computes a lower bound on the log marginal likelihood of words and stop word indicators.
3. Approximates the expected values in the lower bound using samples from an inference network that models the approximate posterior distribution over topics.
The document discusses multiobjective optimization and evolutionary algorithms. It defines multiobjective optimization problems as having multiple objective functions to minimize subject to constraints. Pareto optimal solutions are those that are not dominated by any other solutions in terms of all objectives. Evolutionary algorithms are used to approximate the Pareto front and find Pareto optimal solutions. Non-dominated sorting and crowding distance are used to select the next population in NSGA-II. The hypervolume indicator measures the size of the space covered by the Pareto front approximations.
This document discusses Nyquist's criterion for distortionless transmission of binary signals over a baseband channel. It states that intersymbol interference (ISI) can be eliminated by choosing a transmit filter response P(f) that satisfies the Nyquist criterion. An ideal rectangular pulse shape meets the criterion but is physically unrealizable. A more practical raised cosine pulse is proposed, which introduces a rolloff factor to trade off excess bandwidth for slower decay. The full-cosine case provides additional zero-crossings that aid synchronization but doubles the bandwidth.
This document proposes a modular beamforming architecture for ultrasound imaging that uses FPGA DSP cells to overcome limitations of previous designs. It interleaves the interpolation and coherent summation processes, reducing hardware resources. This allows implementing a 128-channel beamformer in a single FPGA, achieving flexibility like FPGAs but with lower power consumption like ASICs. The design is scalable, allowing a tradeoff between number of channels, time resolution, and resource usage.
The document discusses several key concepts related to the Fourier transform:
1) It introduces the Dirac delta function and explains how it relates to the Fourier transform of exponential and cosine functions.
2) It describes several theorems regarding how the Fourier transform is affected by scaling, shifting, summing and differentiating functions.
3) It explains that both the intensity and phase of a time domain function, and the spectral intensity and phase in the frequency domain, are needed to fully characterize the function and its Fourier transform.
Prim's algorithm finds a minimum spanning tree of a connected weighted graph. It starts with a minimum weight edge and adds the minimum weight edge incident to the growing tree at each step, as long as it does not form a cycle. The algorithm is demonstrated on a sample weighted graph, finding a minimum spanning tree of weight 10 using Prim's algorithm and alphabetical order to break ties.
In this lecture, I will describe how to calculate optical response functions using real-time simulations. In particular, I will discuss td-hartree, td-dft and similar approximations.
CVPR2010: Advanced ITinCVPR in a Nutshell: part 6: Mixtureszukun
1. Gaussian mixtures are commonly used in computer vision and pattern recognition tasks like classification, segmentation, and probability density function estimation.
2. The document reviews Gaussian mixtures, which model a probability distribution as a weighted sum of Gaussian distributions. It discusses estimating Gaussian mixture models with the EM algorithm and techniques for model order selection like minimum description length and Gaussian deficiency.
3. Gaussian mixtures can model images and perform color-based segmentation. The EM algorithm is used to estimate the parameters of Gaussian mixtures by alternating between expectation and maximization steps.
This document discusses the divide and conquer algorithm called merge sort. It begins by explaining the general divide and conquer approach of dividing a problem into subproblems, solving the subproblems recursively, and then combining the solutions. It then provides an example of how merge sort uses this approach to sort a sequence. It walks through the recursive merge sort algorithm on a sample input. The document explains the merge procedure used to combine the sorted subproblems and proves its correctness. It analyzes the running time of merge sort using recursion trees and determines it is O(n log n). Finally, it introduces recurrence relations and methods like substitution, recursion trees, and the master theorem for solving recurrences.
The document discusses the Discrete Fourier Transform (DFT). It explains that the DFT represents a finite-length sequence by the samples of its Discrete-Time Fourier Transform (DTFT). These samples are called the DFT coefficients of the sequence. The DFT provides a transformation between the time and frequency domains. It has various properties like linearity, duality, and relationships between shifting sequences and their DFTs. Circular convolution in the time domain can be computed as multiplication of DFT coefficients in the frequency domain. Examples are provided to illustrate these concepts.
The document discusses the divide and conquer algorithm design technique. It begins by explaining the basic approach of divide and conquer which is to (1) divide the problem into subproblems, (2) conquer the subproblems by solving them recursively, and (3) combine the solutions to the subproblems into a solution for the original problem. It then provides merge sort as a specific example of a divide and conquer algorithm for sorting a sequence. It explains that merge sort divides the sequence in half recursively until individual elements remain, then combines the sorted halves back together to produce the fully sorted sequence.
This document summarizes several numerical methods for solving the advection and wave equations, including:
1) FTCS (Forward Time Centered Space), which is unconditionally unstable. Lax and Lax-Wendroff add diffusion terms to stabilize FTCS.
2) CTCS (Centered Time Centered Space), which is conditionally stable for Courant numbers ≤ 1.
3) Upwinding and Beam-Warming methods, which use points trailing the wave to ensure stability for large Courant numbers.
4) The Box method, which is stable for any Courant number by using points at multiple time levels.
Boundary conditions for the wave equation
This document provides an overview of Fourier analysis in 3 paragraphs or less:
Fourier analysis is a method of representing periodic and aperiodic functions as the sum of trigonometric functions like sines and cosines. It was developed by Joseph Fourier who showed that any signal could be represented as a sum of pure tones. The Fourier transform converts signals between the time and frequency domains, allowing signals to be analyzed by their frequency content. Fourier analysis has applications in fields like signal processing, image processing, acoustics, telecommunications, partial differential equations, geology and more. It provides the foundation for understanding how signals are represented and processed in both continuous and discrete settings.
The document discusses the Fourier transform, which represents signals in terms of their frequencies rather than polynomials. It originated from Jean Fourier's idea that periodic functions can be represented as a weighted sum of sines and cosines of different frequencies. The Fourier transform generalizes this idea and represents functions as a sum of waves with different amplitudes and phases. It allows representing signals in the frequency domain rather than the spatial domain, making filtering and solving differential equations easier. The Fourier transform and its inverse are defined mathematically. It has many applications in areas like physics, signal processing, and image analysis.
Reproducing Kernel Hilbert Space of A Set Indexed Brownian MotionIJMERJOURNAL
ABSTRACT: This study researches a representation of set indexed Brownian motion { : } X X A A A via orthonormal basis, based on reproducing kernel Hilbert space (RKHS). The RKHS associated with the set indexed Brownian motion X is a Hilbert space of real-valued functions on T that is naturally isometric to 2 L ( ) A . The isometry between these Hilbert spaces leads to useful spectral representations of the set indexed Brownian motion, notably the Karhunen-Loève (KL) representation: [ ] X e E X e A n A n where { }n e is an orthonormal sequence of centered Gaussian variables. In addition, we present two special cases of a representation of a set indexed Brownian motion, when ([0,1] ) d A A and A = A( ) Ls .
Newton's method and Gauss-Newton method can be used to minimize a nonlinear least squares function to fit a vector of model parameters to a data vector. The Gauss-Newton method approximates the Hessian matrix as the Jacobian transpose times the Jacobian, ignoring additional terms, making it faster to compute but less accurate than Newton's method. The Levenberg-Marquardt method interpolates between Gauss-Newton and steepest descent methods to provide a balance of convergence speed and accuracy. Iterative methods like conjugate gradients are useful for large nonlinear problems where storing and inverting the full matrix would be prohibitive. L1 regression provides a more robust alternative to L2 regression for dealing with outliers through minimization of the absolute error rather
This document summarizes several number theory concepts and algorithms including:
1. Mersenne primes which are of the form 2^p - 1 where p is prime. It proves some theorems about their properties.
2. Fermat's Little Theorem and Euler's Theorem which relate to exponents modulo a prime. It includes proofs and an algorithm for computing modular inverses.
3. The Chinese Remainder Theorem and its application to finding solutions to systems of congruences.
4. Polynomial arithmetic over finite fields including finding remainders, GCDs, inverses and doing operations in Fp[x]. It describes using these to construct finite fields.
This document summarizes research on using elliptic curve cryptography based on imaginary quadratic orders. It shows that for elliptic curves over a finite field Fq, if q satisfies certain conditions, the elliptic curve discrete logarithm problem can be reduced to the discrete logarithm problem over the finite field Fp2. This allows the elliptic curve discrete logarithm problem to potentially be solved faster. It then provides examples of how to construct "weak curves" that satisfy the necessary conditions.
This document summarizes several papers on principal component analysis (PCA) with network/graph constraints. It discusses graph-Laplacian PCA (gLPCA) which adds a graph smoothness regularization term to standard PCA. It also covers robust graph-Laplacian PCA (RgLPCA) which uses an L2,1 norm and iterative algorithms. Further, it summarizes robust PCA on graphs which learns the product of principal directions and components while assuming smoothness on this product. Finally, it discusses manifold regularized matrix factorization (MMF) which imposes orthonormal constraints on principal directions.
The document discusses the theory of NP-completeness. It begins by classifying problems as solvable, unsolvable, tractable, or intractable. It then defines deterministic and nondeterministic algorithms, and how nondeterministic algorithms can be expressed. The document introduces the complexity classes P and NP. It discusses reducing one problem to another to prove NP-completeness via transitivity. Several classic NP-complete problems are proven to be NP-complete, such as 3SAT, 3-coloring, and subset sum. The document also discusses how to cope with NP-complete problems in practice by sacrificing optimality, generality, or efficiency.
no U-turn sampler, a discussion of Hoffman & Gelman NUTS algorithmChristian Robert
The document describes the No-U-Turn Sampler (NUTS), an extension of Hamiltonian Monte Carlo (HMC) that aims to avoid the random walk behavior and poor mixing that can occur when the trajectory length L is not set appropriately. NUTS augments the model with a slice variable and uses a deterministic procedure to select a set of candidate states C based on the instantaneous distance gain, avoiding the need to manually tune L. It builds up a set of possible states B by doubling a binary tree and checking the distance criterion on subtrees, then samples from the uniform distribution over C to generate proposals. This allows NUTS to automatically determine an appropriate trajectory length and avoid issues like periodicity that can plague
TopicRNN is a generative model for documents that:
1. Draws a topic vector from a standard normal distribution and uses it to generate words in a document.
2. Computes a lower bound on the log marginal likelihood of words and stop word indicators.
3. Approximates the expected values in the lower bound using samples from an inference network that models the approximate posterior distribution over topics.
The document discusses multiobjective optimization and evolutionary algorithms. It defines multiobjective optimization problems as having multiple objective functions to minimize subject to constraints. Pareto optimal solutions are those that are not dominated by any other solutions in terms of all objectives. Evolutionary algorithms are used to approximate the Pareto front and find Pareto optimal solutions. Non-dominated sorting and crowding distance are used to select the next population in NSGA-II. The hypervolume indicator measures the size of the space covered by the Pareto front approximations.
This document discusses Nyquist's criterion for distortionless transmission of binary signals over a baseband channel. It states that intersymbol interference (ISI) can be eliminated by choosing a transmit filter response P(f) that satisfies the Nyquist criterion. An ideal rectangular pulse shape meets the criterion but is physically unrealizable. A more practical raised cosine pulse is proposed, which introduces a rolloff factor to trade off excess bandwidth for slower decay. The full-cosine case provides additional zero-crossings that aid synchronization but doubles the bandwidth.
This document proposes a modular beamforming architecture for ultrasound imaging that uses FPGA DSP cells to overcome limitations of previous designs. It interleaves the interpolation and coherent summation processes, reducing hardware resources. This allows implementing a 128-channel beamformer in a single FPGA, achieving flexibility like FPGAs but with lower power consumption like ASICs. The design is scalable, allowing a tradeoff between number of channels, time resolution, and resource usage.
The document discusses several key concepts related to the Fourier transform:
1) It introduces the Dirac delta function and explains how it relates to the Fourier transform of exponential and cosine functions.
2) It describes several theorems regarding how the Fourier transform is affected by scaling, shifting, summing and differentiating functions.
3) It explains that both the intensity and phase of a time domain function, and the spectral intensity and phase in the frequency domain, are needed to fully characterize the function and its Fourier transform.
Prim's algorithm finds a minimum spanning tree of a connected weighted graph. It starts with a minimum weight edge and adds the minimum weight edge incident to the growing tree at each step, as long as it does not form a cycle. The algorithm is demonstrated on a sample weighted graph, finding a minimum spanning tree of weight 10 using Prim's algorithm and alphabetical order to break ties.
In this lecture, I will describe how to calculate optical response functions using real-time simulations. In particular, I will discuss td-hartree, td-dft and similar approximations.
CVPR2010: Advanced ITinCVPR in a Nutshell: part 6: Mixtureszukun
1. Gaussian mixtures are commonly used in computer vision and pattern recognition tasks like classification, segmentation, and probability density function estimation.
2. The document reviews Gaussian mixtures, which model a probability distribution as a weighted sum of Gaussian distributions. It discusses estimating Gaussian mixture models with the EM algorithm and techniques for model order selection like minimum description length and Gaussian deficiency.
3. Gaussian mixtures can model images and perform color-based segmentation. The EM algorithm is used to estimate the parameters of Gaussian mixtures by alternating between expectation and maximization steps.
This document discusses the divide and conquer algorithm called merge sort. It begins by explaining the general divide and conquer approach of dividing a problem into subproblems, solving the subproblems recursively, and then combining the solutions. It then provides an example of how merge sort uses this approach to sort a sequence. It walks through the recursive merge sort algorithm on a sample input. The document explains the merge procedure used to combine the sorted subproblems and proves its correctness. It analyzes the running time of merge sort using recursion trees and determines it is O(n log n). Finally, it introduces recurrence relations and methods like substitution, recursion trees, and the master theorem for solving recurrences.
The document discusses the Discrete Fourier Transform (DFT). It explains that the DFT represents a finite-length sequence by the samples of its Discrete-Time Fourier Transform (DTFT). These samples are called the DFT coefficients of the sequence. The DFT provides a transformation between the time and frequency domains. It has various properties like linearity, duality, and relationships between shifting sequences and their DFTs. Circular convolution in the time domain can be computed as multiplication of DFT coefficients in the frequency domain. Examples are provided to illustrate these concepts.
The document discusses the divide and conquer algorithm design technique. It begins by explaining the basic approach of divide and conquer which is to (1) divide the problem into subproblems, (2) conquer the subproblems by solving them recursively, and (3) combine the solutions to the subproblems into a solution for the original problem. It then provides merge sort as a specific example of a divide and conquer algorithm for sorting a sequence. It explains that merge sort divides the sequence in half recursively until individual elements remain, then combines the sorted halves back together to produce the fully sorted sequence.
This document summarizes several numerical methods for solving the advection and wave equations, including:
1) FTCS (Forward Time Centered Space), which is unconditionally unstable. Lax and Lax-Wendroff add diffusion terms to stabilize FTCS.
2) CTCS (Centered Time Centered Space), which is conditionally stable for Courant numbers ≤ 1.
3) Upwinding and Beam-Warming methods, which use points trailing the wave to ensure stability for large Courant numbers.
4) The Box method, which is stable for any Courant number by using points at multiple time levels.
Boundary conditions for the wave equation
This document provides an overview of Fourier analysis in 3 paragraphs or less:
Fourier analysis is a method of representing periodic and aperiodic functions as the sum of trigonometric functions like sines and cosines. It was developed by Joseph Fourier who showed that any signal could be represented as a sum of pure tones. The Fourier transform converts signals between the time and frequency domains, allowing signals to be analyzed by their frequency content. Fourier analysis has applications in fields like signal processing, image processing, acoustics, telecommunications, partial differential equations, geology and more. It provides the foundation for understanding how signals are represented and processed in both continuous and discrete settings.
The document discusses the Fourier transform, which represents signals in terms of their frequencies rather than polynomials. It originated from Jean Fourier's idea that periodic functions can be represented as a weighted sum of sines and cosines of different frequencies. The Fourier transform generalizes this idea and represents functions as a sum of waves with different amplitudes and phases. It allows representing signals in the frequency domain rather than the spatial domain, making filtering and solving differential equations easier. The Fourier transform and its inverse are defined mathematically. It has many applications in areas like physics, signal processing, and image analysis.
Reproducing Kernel Hilbert Space of A Set Indexed Brownian MotionIJMERJOURNAL
ABSTRACT: This study researches a representation of set indexed Brownian motion { : } X X A A A via orthonormal basis, based on reproducing kernel Hilbert space (RKHS). The RKHS associated with the set indexed Brownian motion X is a Hilbert space of real-valued functions on T that is naturally isometric to 2 L ( ) A . The isometry between these Hilbert spaces leads to useful spectral representations of the set indexed Brownian motion, notably the Karhunen-Loève (KL) representation: [ ] X e E X e A n A n where { }n e is an orthonormal sequence of centered Gaussian variables. In addition, we present two special cases of a representation of a set indexed Brownian motion, when ([0,1] ) d A A and A = A( ) Ls .
Newton's method and Gauss-Newton method can be used to minimize a nonlinear least squares function to fit a vector of model parameters to a data vector. The Gauss-Newton method approximates the Hessian matrix as the Jacobian transpose times the Jacobian, ignoring additional terms, making it faster to compute but less accurate than Newton's method. The Levenberg-Marquardt method interpolates between Gauss-Newton and steepest descent methods to provide a balance of convergence speed and accuracy. Iterative methods like conjugate gradients are useful for large nonlinear problems where storing and inverting the full matrix would be prohibitive. L1 regression provides a more robust alternative to L2 regression for dealing with outliers through minimization of the absolute error rather
This document summarizes several number theory concepts and algorithms including:
1. Mersenne primes which are of the form 2^p - 1 where p is prime. It proves some theorems about their properties.
2. Fermat's Little Theorem and Euler's Theorem which relate to exponents modulo a prime. It includes proofs and an algorithm for computing modular inverses.
3. The Chinese Remainder Theorem and its application to finding solutions to systems of congruences.
4. Polynomial arithmetic over finite fields including finding remainders, GCDs, inverses and doing operations in Fp[x]. It describes using these to construct finite fields.
This document summarizes research on using elliptic curve cryptography based on imaginary quadratic orders. It shows that for elliptic curves over a finite field Fq, if q satisfies certain conditions, the elliptic curve discrete logarithm problem can be reduced to the discrete logarithm problem over the finite field Fp2. This allows the elliptic curve discrete logarithm problem to potentially be solved faster. It then provides examples of how to construct "weak curves" that satisfy the necessary conditions.
This document summarizes several papers on principal component analysis (PCA) with network/graph constraints. It discusses graph-Laplacian PCA (gLPCA) which adds a graph smoothness regularization term to standard PCA. It also covers robust graph-Laplacian PCA (RgLPCA) which uses an L2,1 norm and iterative algorithms. Further, it summarizes robust PCA on graphs which learns the product of principal directions and components while assuming smoothness on this product. Finally, it discusses manifold regularized matrix factorization (MMF) which imposes orthonormal constraints on principal directions.
A Parallel Branch And Bound Algorithm For The Quadratic Assignment ProblemMary Calkins
This document summarizes a parallel branch and bound algorithm for solving the quadratic assignment problem (QAP). Key points:
- The algorithm was implemented on a Cray X-MP asynchronous shared-memory multiprocessor.
- For problems of size n=10, the algorithm achieved near-linear speedup of around n using n processors. Good results were also obtained for a classic QAP problem of size n=12.
- The algorithm uses a "polytomic" branching rule to generate multiple successors at each node, constraining subproblems and allowing minimal information to be stored per node.
This summary provides the key details from the document in 3 sentences:
The document presents a new iterative method (M2 method) for determining the exact solution to a parametric linear programming problem where the objective function and constraints contain parameters. The M2 method exploits the concept of a p-solution to a square linear interval parametric system and iteratively reduces the parameter domain while maintaining upper and lower bounds on the optimal objective value. A numerical example is given to illustrate the new iterative approach for solving parametric linear programming problems.
This document summarizes techniques for solving the eigenvalue problem Kφ=λMφ to find the eigenvalues λ and eigenvectors φ of the stiffness matrix K and mass matrix M. It describes the Rayleigh-Ritz method which approximates eigenvalues and eigenvectors by minimizing the Rayleigh quotient. It also outlines the subspace iteration method which iteratively improves an initial subspace to converge on the desired eigenpairs. The method uses Rayleigh-Ritz on the projected matrices Kk+1 and Mk+1 at each iteration to refine the approximations. With a sufficiently large initial subspace that is not M-orthogonal to the sought eigenvectors, the approximations will converge to the lowest eigenvalues and eigenvectors.
A Level Set Method For Multiobjective Combinatorial Optimization Application...Scott Faria
This document proposes a new algorithm for computing all Pareto optimal solutions to multiobjective combinatorial optimization problems based on the level set method. The algorithm generates level sets in order of increasing objective function values for one objective at a time, checking if each solution is contained in the other level sets and dominates previously found solutions. It relies on the ability to find the K best solutions to a single objective combinatorial problem. The method is applied to the multiobjective quadratic assignment problem and computational results are presented.
Heuristics for counterexamples to the Agrawal ConjectureAmshuman Hegde
This document presents heuristics for constructing counterexamples to the Agrawal Conjecture. It generalizes an earlier proposition given by Lenstra and Pomerance by showing that their arguments can be applied to any prime number r that is congruent to 1 modulo 4. A second generalization is presented that allows the number n to be composed of prime power factors rather than just prime factors. Finally, a rough estimate is given suggesting that there should be at least e^{T^2(1-5/m)} counterexamples below e^{T^2} for large T.
The document provides an overview of concepts in functional analysis that will be covered in a math camp, including: function spaces, metric spaces, dense subsets, linear spaces, linear functionals, norms, Euclidean spaces, orthogonality, separable spaces, complete metric spaces, Hilbert spaces, and convex functions. Examples are given for each concept to illustrate the definitions.
DOI: 10.13140/RG.2.2.24591.92329/9
The Pythagorean theorem is perhaps the best known theorem in the vast world of mathematics.A simple relation of square numbers, which encapsulates all the glory of mathematical science, isalso justifiably the most popular yet sublime theorem in mathematical science. The starting pointwas Diophantus’ 20 th problem (Book VI of Diophantus’ Arithmetica), which for Fermat is for n= 4 and consists in the question whether there are right triangles whose sides can be measuredas integers and whose surface can be square. This problem was solved negatively by Fermat inthe 17 th century, who used the wonderful method (ipse dixit Fermat) of infinite descent. Thedifficulty of solving Fermat’s equation was first circumvented by Willes and R. Taylor in late1994 ([1],[2],[3],[4]) and published in Taylor and Willes (1995) and Willes (1995). We presentthe proof of Fermat’s last theorem and other accompanying theorems in 4 different independentways. For each of the methods we consider, we use the Pythagorean theorem as a basic principleand also the fact that the proof of the first degree Pythagorean triad is absolutely elementary anduseful. The proof of Fermat’s last theorem marks the end of a mathematical era; however, theurgent need for a more educational proof seems to be necessary for undergraduates and students ingeneral. Euler’s method and Willes’ proof is still a method that does not exclude other equivalentmethods. The principle, of course, is the Pythagorean theorem and the Pythagorean triads, whichform the basis of all proofs and are also the main way of proving the Pythagorean theorem in anunderstandable way. Other forms of proofs we will do will show the dependence of the variableson each other. For a proof of Fermat’s theorem without the dependence of the variables cannotbe correct and will therefore give undefined and inconclusive results . It is, therefore, possible to prove Fermat's last theorem more simply and equivalently than the equation itself, without monomorphisms. "If one cannot explain something simply so that the last student can understand it, it is not called an intelligible proof and of course he has not understood it himself." R.Feynman Nobel Prize in Physics .1965.
The document discusses block ciphers and stream ciphers. It defines block ciphers as encrypting data in fixed-size blocks using the same key for each block. Stream ciphers encrypt individual bits or characters, generating a unique key for each bit using a pseudorandom number generator. The document then focuses on stream ciphers, describing synchronous and self-synchronizing stream ciphers, linear feedback shift registers (LFSRs) used to generate keystreams, and how to determine a stream cipher's characteristic polynomial from its keystream bits.
Linear cryptanalysis is a method used to break encryption standards like DES. It involves finding linear approximations between plaintext, ciphertext, and key bits that hold with probability greater than 50%. These approximations are used to determine partial key bits using maximum likelihood algorithms on known or ciphertext-only data. For S-DES, the method finds a linear expression involving S-box inputs/outputs that predicts a key bit with 78% accuracy, allowing recovery of multiple key bits.
The document discusses orthogonal polynomials, focusing on Legendre and Chebyshev polynomials. It introduces Hilbert spaces and self-adjoint operators, describing properties like Hermitian matrices having real eigenvalues. It defines the L2 space and shows how differential operators can act as self-adjoint. Legendre polynomials are defined using Rodrigue's formula and their generating function is explored. The first few Legendre polynomials are shown.
Tucker tensor analysis of Matern functions in spatial statistics Alexander Litvinenko
1. Motivation: improve statistical models
2. Motivation: disadvantages of matrices
3. Tools: Tucker tensor format
4. Tensor approximation of Matern covariance function via FFT
5. Typical statistical operations in Tucker tensor format
6. Numerical experiments
The document summarizes the 1988 paper "Ramanujan Graphs" by Lubotzky, Phillips, and Sarnak, which constructed the first verified sequence of Ramanujan graphs with fixed degree k and arbitrarily large order. The paper establishes:
1) A multiplicative group Λ of integer quaternions with norm pk that factors uniquely.
2) A homomorphism from Λ to PGL(2,Zq) or PSL(2,Zq) that maps the Cayley graph of Λ isomorphically onto a Cayley graph Xp,q of the linear group.
3) Using deep number theory results on representations of integers as sums of squares,
This document summarizes a research paper about nonexistence results for certain Griesmer codes of dimension 4 over finite fields. It begins by providing background on optimal linear codes and the Griesmer bound. It then presents two theorems: Theorem 2 improves valid ranges for the parameter r in an earlier theorem, and Theorem 3 proves that the Griesmer bound is attained for specific code parameters when q is greater than or equal to 7. The document provides proofs for Theorems 2 and 3 using a geometric method involving partitions of projective spaces and properties of minihypers and arcs.
Quantitative norm convergence of some ergodic averagesVjekoslavKovac1
The document summarizes quantitative estimates for the convergence of multiple ergodic averages of commuting transformations. Specifically, it presents a theorem that provides an explicit bound on the number of jumps in the Lp norm for double averages over commuting Aω actions on a probability space. The proof transfers the structure of the Cantor group AZ to R+ and establishes norm estimates for bilinear averages of functions on R2+. This allows bounding the variation of the double averages and proving the theorem.
An Algorithm For The Combined Distribution And Assignment ProblemAndrew Parish
This document presents an algorithm for solving the combined distribution and assignment problem using generalized Benders' decomposition. The algorithm formulates the problem as a modified distribution problem with a minimax objective function instead of a linear one. It solves this master problem using the Newton-Kantorovich method for nonlinear concave programming problems with linear constraints. The algorithm iterates between solving the assignment problem given a distribution and solving the modified distribution problem subject to optimality constraints from the assignment problem. When the solution converges, it provides the optimal traffic flows for both distribution and assignment.
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
-------------------------------------------------------------------------------
Find out more about ISO training and certification services
Training: ISO/IEC 27001 Information Security Management System - EN | PECB
ISO/IEC 42001 Artificial Intelligence Management System - EN | PECB
General Data Protection Regulation (GDPR) - Training Courses - EN | PECB
Webinars: https://pecb.com/webinars
Article: https://pecb.com/article
-------------------------------------------------------------------------------
For more information about PECB:
Website: https://pecb.com/
LinkedIn: https://www.linkedin.com/company/pecb/
Facebook: https://www.facebook.com/PECBInternational/
Slideshare: http://www.slideshare.net/PECBCERTIFICATION
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
2. First Steps
To do Pairing based Crypto we need
two things
Efficient algorithms
Suitable elliptic curves
We have got both! (Maybe not quite
enough suitable curves?)
3. What’s a Pairing?
e(P,Q) where P and Q are points on
an elliptic curve.
It has the property of bilinearity
e(aP,bQ) = e(bP,aQ) = e(P,Q)ab
We use the Tate pairing.
4. Hard problems…
1. Given aP and P, its hard to find a
2. Given e(P,Q)a and e(P,Q) its hard
to find a.
3. Given {P,sP,aP,Q,sQ,bQ} its hard
to find e(P,Q)sab
5. Making it secure
Recall that on a pairing friendly
elliptic curve E(Fq), the curve order
has a large prime divisor r, and
where k is the smallest integer such
that r|qk-1
k is the embedding degree, a.k.a.
the security multiplier
Pairings evaluates as element in Fqk
6. Making it secure
If r is 160-bits, then Pohlig-Hellman
attacks will take ~ 280 steps
If k.lg(q) ~ 1024 bits, Discrete Log
attacks will also take ~ 280 steps
So we can achieve appropriate
levels of cryptographic security
7. Modified Tate Pairing
Supersingular curves support a distortion
map, Φ(Q) which evaluates as a point on
E(Fqk) if Q is on E(Fq).
So choose P and Q on E(Fq), then
ê(P,Q) =e(P, Φ(Q))
Is an alternative, nicer (Type 1) pairing,
with the extra property ê(P,Q) = ê(Q,P)
8. A quick protocol..
Sakai and Kasahara non-interactive
ID-based key exchange.
A trusted authority with secret s
give Alice sA, where A is derived in
a public way from Alices identity.
The trusted authority gives Bob sB.
They share a key ê (sA,B)=ê (sB,A)!
No interaction required!
9. What choices?
If q=p a prime, maximum k=2
If q=2m, maximum k=4
If q=3m, maximum k=6
We need group size r ≥ 160 bits
We need qk ~ 1024 bits
We know r | q+1-t
(t is trace of the Frobenius ≤ 2 √q)
10. Constrained…
These constraints are… well…
constraining!
I have an irrational aversion to F3m!
So what about Hyperelliptic curves…?
Not very promising in practice…
Fortunately, we have an alternative
choice – certain families of ordinary
elliptic curves over Fp
11. Ordinary Elliptic Curves
There are the MNT curves, with
k={3,4,6}
There are Freeman curves with
k=10
There are Barreto-Naehrig curves
with k=12
12. Ordinary Elliptic Curves
These curves all have r~p, which is
nice, as it means P can be over the
smallest possible field for given
level of security
If we relax this, many more families
can be found (e.g. Brezing-Weng)
If we allow lg(r) ≤ 2.lg(p) then
curves for any k are plentiful
(Cocks-Pinch)
13. The bad news..
No distortion map (Type 3 pairing)
In e(P,Q), while P can be in E(Fp), Q
cannot.
The best we can do is to put Q on a
lower order “twist” E(Fpk/w), where always
w=2, (but w=4 and w=6 are possible).
For example for BN curves we can use
w=6 and put Q on E(Fp2)
e(P,Q) ≠ e(Q,P)
14. Implementation
For simplicity (for now)
Assume k=2d, d=1, p=3 mod 4
Elements in Fp2 can be represented
as (a+ib), where a and b are in Fp
and i=√-1 because -1 is a quadratic
non-residue (think “imaginary
number”)
Assume P is in E(Fp), Q in E(Fp2)
15. Basic Algorithm for e(P,Q)
m ← 1, T ← P
for i=lg(r)-1 downto 0 do
m ← m2.lT,T (Q)/v2T(Q)
T ← 2.T
if ri = 1
m ← m.lT,P(Q)/vT+P(Q)
T=T+P
end if
end for Millers Algorithm
m ← m(p-1) Final Exponentiation
return m(p+1)/r
16. lT,T(Q) = (yq-yj) – λj(xq-xj)
v2T(Q) =xq-xj+1
Explaining the Algorithm
Q(xq,yq)
T=(xj,yj)
xq-xj
yq-yj
Line of slope λj
xj+1,yj+1
17. Optimizations
Choose r to have a low Hamming weight
By cunning choice of Q as a point on the
twisted curve and using only even k=2d,
the v(.) functions become elements in Fpd
and hence get “wiped out” by the final
exponentiation, which always includes pd-1
as a factor of the exponent.
Now the algorithm simplifies to…
18. Improved Algorithm
m ← 1, T ← P
for i=lg(r)-1 downto 0 do
m ← m2.lT,T (Q)
T ← 2.T
if ri = 1
m ← m.lT,P(Q)
T=T+P
end if
end for
m ← m(p-1)
return m(p+1)/r
19. A useful Observation..
Observe the line m ← m(p-1)
Part of the final exponentiation –
raising to the power of (pk-1)/r
Now for any c in Fp, c(p-1) = 1 mod p
(Fermat)
Therefore m can be multiplied by
any constant at any time in the
Miller loop without effecting the
final result!
20. Further optimization ideas
Truncate the loop in Miller’s
algorithm, and still get a viable
pairing.
Optimize the final exponentiation
Exploit the Frobenius – an element
of any extension field Fqk can easily
be raised to any power of q. For
example in Fp2
(a+ib)p = (a-ib)
21. Further optimization ideas
Precomputation!
If P is fixed, all the T values can be
precomputed and stored – with
significant savings.
P may be a fixed public value or a
fixed secret key – depends on the
protocol.
22. The ηT pairing - 1
For the supersingular curves of low
characteristic, the basic algorithm
can be drastically simplified by
integrating the distortion map, the
point multiplication, and the action
of the Frobenius directly into the
main Miller loop. Also exploits the
simple group order. This is a Type 1
pairing.
23. The ηT pairing - 2
In characteristic 2, k=4.
r =2m ± 2[(m+1)]/2 + 1
Elements in F2m are represented as a
polynomial with m coefficients in F2
Elements in the extension field F24m are
represented as a polynomial with 4
coefficients in F2m
e.g. a+bX+cX2+dX3 represented as
[a,b,c,d].
24. The ηT pairing - 3
Let s=[0,1,1,0] and t=[0,1,0,0] (derived
from the distortion map)
Then on the supersingular curve
y2+y=x3+x+b, where b=0 or 1
And m= 3 mod 8
A pairing e(P,Q), where P=(xP,yP) and
Q=(xQ,yQ), can be calculated as
25. The ηT pairing - 4
u←xP+1
f←u(xP+xQ+1)+yP+yQ+b+1+(u+xQ)s+t
for i=1 to (m+1)/2 do
u←xP xP←√xP yP←√yP
g←u(xP+xQ)+yP+yQ+xP+(u+xQ)s+t
f←f.g xQ←xQ
2 yQ←yQ
2
end for
return f(22m-1)(2m-2(m+1)/2 +1)
26. The ηT pairing - 5
This is very fast! <5 seconds on an
msp430 wireless sensor network
node, with m=271 (C – no asm)
Note truncated loop (m+1)/2.
Final exponentiation very fast using
Frobenius.
Ideal in low power, resource
constrained environment.
27. Ate Pairing for ordinary curves E(Fp)
Truncated Loop pairing, related to Tate pairing.
Number of iterations in Miller loop may be much
shorter – lg(t-1) instead of lg(r), and for some
families of curves t can be much less than r
Parameters “change sides”, now P is on the
twisted curve and Q is on the curve over the
base field.
Works particularly well with curves that allow a
higher order (sextic) twist.
28. Extension Field Arithmetic
For non-supersingular curves over
Fpk there is a need to implement
very efficient extension field
arithmetic.
A new challenge for cryptographers
(although XTR and OEFs require it)
Simple generic polynomial
representation will be slow, and
misses optimization opportunities.
29. Towering extensions
Consider p=5 mod 8
Then a suitable representation for
Fp2 would be (a+xb), where a,b are
in Fp, x=(-2)1/2, as -2 will be a QNR.
Then a suitable representation for
Fp4 would be (a+xb), where a,b are
in Fp2, x=(-2)1/4
Etc!
30. Towering extensions
In practise it may be sufficient to
restrict k=2i3j for i≥1, j≥0, as this
covers most useful cases.
So only need to deal with cubic and
quadratic towering.
These need only be efficiently
developed once (using Karatsuba,
fast squaring, inversion, square
roots etc.)
31. Multiplication & Squaring
(quadratic extension)
Using Karatsuba..
(a+ib)(c+id) = ac-
bd+i[(a+b)(c+d)-ac-bd]
Requires 3 modmuls…
OR 3 multiplications and 2 modular
reductions (“lazy” reduction)
(a+ib)(a+ib)=(a+b)(a-b)+i.2ab
32. Multiplication & Squaring
(cubic extension)
Toom-Cook for multiplication?
Chung-Hasan for squaring?
A problem with both methods is the
requirement for division by small
constants…
Not a problem thanks to the “useful
observation”!
33. Choice of irreducible polynomial
A binomial is the simplest, xn+δ,
and the easiest to tower over.
For example for k=12 BN curves
X6+(1+√-2) as a sextic tower over
x2+2, where (1+√-2) is neither a
cube nor a square.
..and so the sextic extension can be
constructed as a cubic over a
quadratic
34. Choice of irreducible polynomial
In general the k-th extension can
often be constructed as
xk/2+(α+√β) towered over x2+√β,
where α, β in {-1,+1,-2,+2}
In practise this seems to work well,
and the small values for α, β lead to
useful speed-ups.
Not too restrictive..
35. The Final Exponentiation - 1
Note that the exponent is (pk-1)/r
This is a number dependent only on
fixed, system parameters
So maybe we can choose p, k and r
to make it easier (Low Hamming
Weight?)
If k=2d is even then
(pk-1)/r = (pd-1).[(pd+1)/r]
36. The Final Exponentiation - 2
We know that r divides (pd+1) and
not (pd-1) from the definition of k.
Exponentiation to the power of pd is
“for free” using the Frobenius, so
exponentiation to the power of pd-1
costs just a Frobenius and a single
extension field division – cheap!
37. The Final Exponentiation - 3
In fact we know that the
factorisation of (pk-1) always
includes Φk(p), where Φk(.) is the k-
th cyclotomic polynomial, and that
r|Φk(p).
For example
p6-1 = (p3-1)(p+1)(p2-p+1)
Where Φ6(p) = p2-p+1
38. The Final Exponentiation - 4
So the final exponent is general
breaks down as…
(pd-1).[(pd+1)/Φk(p)].Φk(p)/r
All except the final Φk(p)/r part can
be easily dealt with using the
Frobenius.
39. The Final Exponentiation - 5
However this “hard” exponent e can
always be represented to base p as
e=e0+e1p+e2p2…
fe = fe0
+e1
p+e2
p2… = fe0 .(fp)e1.(fp2
)e2…
Which can be calculated using the
Frobenius and the well known method of
multi-exponentiation.
40. The Final Exponentiation - 6
Another idea is to exploit the special
form of the “hard part” of the final
exponentiation for a particular curve
If k is divisible by 2 the pairing
value can be “compressed” times 2
and Lucas exponentiation used.
If k is divisible by 3 the pairing
value can be “compressed” times 3
and XTR exponentiation used.
41. Case study – k=6 MNT curves
Assuming a prime order curve, then
the hard part of the final exponent
is (p2-p+1)/r, where r=p+1-t
Then the exponent is p±σ, where σ
~ t
So the final exponentiation is fp.f±σ
Which just costs a Frobenius and
one half-length exponentiation!
42. Products of pairings
Arises in many protocols
e(P,Q).e(R,S) 3 ideas
The multiplication of P and R by r occur
in “lock-step”, so use Montgomery’s
trick, affine coordinates, only one
modular inversion
Share the “Miller variable” m (so only
one squaring of m in the Miller loop)
Share the final exponentiation
43. Implementation – more complex than RSA or ECC!
There are many choices of curves,
and of embedding degrees, and of
pairings. It is not at all obvious
which is “best” for any given
application. The optimal pairing to
use depends not just on the
security level, but also on the
protocol to be implemented.
44. Implementation – more complex than RSA or ECC!
For example (a) p~512 bits and k=2, or
(b) p~170 bits and k=6 MNT curve?
On the face of it same security.
Smaller p size means faster base field point
multiplications – so (b) looks better
Which is important only if point multiplications are
required by the protocol.
(a) pairing is much faster if precomputation is possible
(b) must be used for short signatures
(b) requires Q on the twist E’(Fp3) which is more complicated than
(a) for which Q can be on E’(Fp)
The (b) curves are hard to find, whereas (a) types are plentiful.
(a) is much simpler to implement with the smaller extension.. Smaller code
45. Implementation – more complex than RSA or ECC!
For maximum efficiency each
implementation must be highly
specialised according to its
parameters.
A k=2 Cocks-Pinch implementation
will be quite different from a k=6
MNT implementation.