From the well-known Fibonacci sequence, the number F-10=55=5 center dot 11 is an example not only as a repdigit (a number with only one distinct digit) but also as a product of two repdigits with consecutive lengths, ...
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From the well-known Fibonacci sequence, the number F-10=55=5 center dot 11 is an example not only as a repdigit (a number with only one distinct digit) but also as a product of two repdigits with consecutive lengths, 5 and 11. Here we find all the Fibonacci numbers that can be written as the product of k repdigits with consecutive lengths.
The NTRU public key cryptosystem was proposed by Hoffstein, Pipher and Silverman in 1996. NTRU is one of the most widely used public key cryptosystems and its security has been an active research topic. In 1977, coppe...
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ISBN:
(纸本)9781509059423
The NTRU public key cryptosystem was proposed by Hoffstein, Pipher and Silverman in 1996. NTRU is one of the most widely used public key cryptosystems and its security has been an active research topic. In 1977, coppersmith and Shamir applied new lattice basis reduction techniques to cryptanalyze the scheme, to discover either the original secret key, or an alternative secret key which is equally useful in decoding the ciphertexts. In 2014, A. Nitaj gave cryptanalysis of NTRU with two public keys and compared with lattice attack given by Coppersmith and Shamir. In this paper, we are generalizing the idea of A. Nitaj and presenting cryptanalysis of NTRU with n public keys.
This paper proposes a combined forward and backward lattice reduction scheme to improve estimation of transmitted signals in lattice-reduction aided (LRA) MMSE MIMO systems. The cross-correlation between the forward a...
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ISBN:
(纸本)9781424417223;9781424417216
This paper proposes a combined forward and backward lattice reduction scheme to improve estimation of transmitted signals in lattice-reduction aided (LRA) MMSE MIMO systems. The cross-correlation between the forward and the backward transform matrices is also analyzed to make sure that the proposed detector achieves more reliable estimates. The proposed detector achieves better BER performance than the conventional LRA detector. The achieved BER curve is improved by 3.5dB at BER=10(-5) over the curve of the conventional LRA MMSE detector in the 8x8 MIMO.
Lenstra-Lenstra-Lovasz (lll) algorithm, which is one of the lattice reduction (LR) techniques, has been extensively used to obtain better basis of the channel matrix. In this paper, we jointly apply Seysen's latti...
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ISBN:
(纸本)9781424451234
Lenstra-Lenstra-Lovasz (lll) algorithm, which is one of the lattice reduction (LR) techniques, has been extensively used to obtain better basis of the channel matrix. In this paper, we jointly apply Seysen's lattice reduction algorithm (SA), instead of lll, with the conventional linear precoding algorithms. Since SA obtains more orthogonal lattice basis compared to that obtained by lll, lattice reduction aided (LRA) precoding based on SA algorithm outperforms the LRA precoding with lll. Simulation results demonstrate that a gain of 0.5dB at target BER of 10(-5) is achieved when SA is used instead of lll for the LR stage.
In the recent twenty years, lattice basis reduction algorithm, such as the celebrated lll (A.K. Lenstra-H.W. Lenstra Jr.-L. Lovasz) algorithm plays an important role in the public-key schemes design and cryptanalysis....
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ISBN:
(纸本)9783030367114;9783030367107
In the recent twenty years, lattice basis reduction algorithm, such as the celebrated lll (A.K. Lenstra-H.W. Lenstra Jr.-L. Lovasz) algorithm plays an important role in the public-key schemes design and cryptanalysis. To assess the security of the public-key cryptosystems by lattice reduction algorithms, the most time-consuming part is running the lattice reduction algorithm on the corresponding lattice with high dimension or big coefficients. In this paper, we investigate secure out-sourcing for lattice basis reduction for the first time. We propose a lattice basis reduction scheme such that the clients can outsource their main computation workloads to the untrusted cloud servers. We employ rounding technique and unimodular transformation matrix for privacy protection before sending the target lattice basis to the cloud. The results returned from the cloud need to be decrypted and verified to satisfy reduction conditions. The experimental results indicate that our scheme is correct, efficient and feasible.
We address the problem of computing a good floating-point-coefficient polynomial approximation to a function, with respect to the supremum norm. This is a key step in most processes of evaluation of a function. We pre...
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ISBN:
(纸本)9780769528540
We address the problem of computing a good floating-point-coefficient polynomial approximation to a function, with respect to the supremum norm. This is a key step in most processes of evaluation of a function. We present a fast and efficient method, based on lattice basis reduction, that often gives the best polynomial possible and most of the time returns a very good approximation.
Co-occurrence matrices as sources of second order statistical descriptors are commonly used in texture classification tasks. To generate such a matrix, we need a position vector to check possible intensity frequencies...
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ISBN:
(纸本)9781509040117
Co-occurrence matrices as sources of second order statistical descriptors are commonly used in texture classification tasks. To generate such a matrix, we need a position vector to check possible intensity frequencies in its endpoints. In this paper, we propose an efficient algorithm to locate such position vectors according which the pattern of the texture repeats and thus, the descriptors (Haralick features) derived from the co-occurrence matrix are capable to characterize the regularity of the pattern. The essence of our approach is to look for vectors that span well-approximating grids defined by reference points obtained by quantizing the input image. To extract such grids we use the lll algorithm, which has a polynomial running time. Thus, we have a much more efficient solution than e.g. a brute force based search. Our results show that the proposed approach is capable to suggest position vectors for an efficient co-occurrence matrix based texture analysis.
As the large-scale multiple-input multiple-output (MIMO) systems have been advanced in wireless communication, the low complexity and high performance receiver technique have been required. Recently, lattice reduction...
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ISBN:
(纸本)9781509008056
As the large-scale multiple-input multiple-output (MIMO) systems have been advanced in wireless communication, the low complexity and high performance receiver technique have been required. Recently, lattice reduction technique have attracted attention in MIMO detection. Especially, lattice reduction aided linear detection like zero-forcing (ZF) can largely improve the performance with low complexity. Among all the lattice reduction algorithms, the Lenstra-Lenstra-Lovasz (lll) algorithm is well-known and widely used algorithm. lll algorithm reduces the basis of channel matrix by using two conditions and it adopts a parameter in order to get nearly orthogonal basis. Although the parameter is defined range, a constant value is commonly used. However it can't be said that the constant value is the best value for all MIMO system. In this paper, we propose an appropriate parameter to reduce computational complexity in lll algorithm for ZF detection and we also propose an architecture to adapt our proposed parameter in MIMO detection. The proposed parameter is showed simply and corresponds to the number of antennas. Simulation results show that the proposed parameter provides lll lattice reduction aided ZF detection achieving the same performance as the widely used constant value with lower complexity and also correspond to every MIMO system including large-scale MIMO system.
Recent studies have investigated lattice-reduction (LR) preprocessing technique for multiple-input multiple-output (MIMO) detection. However, if LR is applied to the orthogonal-frequency-division-multiplexing (OFDM) s...
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ISBN:
(纸本)9781457705397
Recent studies have investigated lattice-reduction (LR) preprocessing technique for multiple-input multiple-output (MIMO) detection. However, if LR is applied to the orthogonal-frequency-division-multiplexing (OFDM) system, its complexity and latency increase greatly because of the large number of sub-carriers. This paper proposes a new processing architecture for LR-aided MIMO-OFDM system. This LR processing architecture reduces the number of iteration loops by using preprocessing matrix of adjacent sub-carrier. Beside, the grouping of sub-carriers can break the long critical computational path so as to comprise the computational complexity and latency. We simulate the proposed LR-aided MIMO-OFDM processing in the 3GPP-LTE system. The proposed method not only reduces the computational complexity but also shortens the latency for the lattice reduction.
Recently, Nitaj and Douh presented a new attack on RSA with a composed decryption exponent. To be specific, they assumed that the decryption exponent in RSA is of the form d = Md-1+d(0) where M is a known positive int...
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ISBN:
(纸本)9783319167459;9783319167442
Recently, Nitaj and Douh presented a new attack on RSA with a composed decryption exponent. To be specific, they assumed that the decryption exponent in RSA is of the form d = Md-1+d(0) where M is a known positive integer and d(0) and d(1) are two suitably small unknown integers. They gave a lattice-based decryption exponent recovery attack on this kind of RSA when the exponent d is under a larger bound than the well-known one N-0.292 given by Boneh and Durfee. In this paper, we reconsider the same problem and present a new attack by using the unravelled linearization technique proposed by Herrmann and May at Asiacrypt 2009. Our result is theoretically better than that of Nitaj and Douh and more importantly, is more efficient in terms of the dimension of lattice involved in the attack.
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