Shahram Etemadi | University of Isfahan (original) (raw)

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Papers by Shahram Etemadi

Proceedings First International IEEE Symposium Intelligent Systems

This paper describes an encryption system for analog signals based on permutation of samples. The... more This paper describes an encryption system for analog signals based on permutation of samples. The scrambling algorithm is based on the permutation of the samples and provides highly secured scrambled signal by permuting a large number of those samples. The algorithm for generation the permutation matrices is explained. Important items to be considered in designing the system are discussed such as choice and construction of permutation matrices, and configuration of the practical scrambling system. C programming language was used for simulation. The results of simulation and tests shows that proposed scrambling achieve extremely high-level security. The method of choice and generation of permutation matrices, Tompkin-Paig algorithm and maximum length shift register are discussed. Simulations of different parts of the system, include scrambler, descrambler and generation of permutation matrices programs are provided. Miscellaneous methods of objective tests are described. Theoretical and simulation results of these tests are also provided.

IETE Journal of Research, 2013

ABSTRACT In this paper, a random bit sequence generator based on chaotic maps is introduced and i... more ABSTRACT In this paper, a random bit sequence generator based on chaotic maps is introduced and implemented. In this generator, two chaotic map functions with two different keys are used. The Bifurcation diagram is used to calculate the initial state of the chaotic maps in order to produce the output random bit sequence. Chaotic Logistic and Tent maps classically are defined in an analogue space. In order to implement these chaotic maps on a hardware digital platform, these chaotic maps are modified. Digital chaotic Logistic and Tent maps are introduced. A design for implementation of these modified chaotic maps is also presented. The output bits of two chaotic maps are EX-ORed to produce a random sequence of 1 000 000 bits. These designs are implemented on Field Programmable Gate Array, and the results are reported. The proposed designs are tested by producing 100 samples of 1 000 000 bits, and they pass the standard Federal Information Processing Standard 140-1 and National Institute of Standards and Technology statistical tests for random bit generators.

Arabian Journal for Science and Engineering, 2014

The paper proposes an algorithm for image encryption using the random bit sequence generator and ... more The paper proposes an algorithm for image encryption using the random bit sequence generator and based on chaotic maps. Chaotic Logistic and Tent maps are used to generate required random bit sequences. Pixels of the plain image are permuted using these chaotic functions, and then the image is partitioned into eight bit map planes. In each plane, bits are permuted and substituted according to random bit and random number matrices; these matrices are the products of those functions. The pixels and bit maps permutation stage are based on a chaotic random Ergodic matrix. This chaotic encryption method produces encrypted image whose performance is evaluated using chi-square test, correlation coefficient, number of pixel of change rate (NPCR), unified average changing intensity (UACI), and key space. The histogram of encrypted image is approximated by a uniform distribution with low chi-square factor. Horizontal, vertical, and diagonal correlation coefficients of two adjacent pixels of encrypted image are calculated. These factors are improved compared to other proposed methods. The NPCR and UACI values of encrypted image are also calculated. The result shows that a swift change in the original image will cause a significant change in the ciphered image. Total key space for the proposed method is (2 ∧ 2,160), which is large enough to protect the proposed encryption image against any bruteforce attack.

faculty.kfupm.edu.sa

Abstract-The art of security of voice communication in what is known as encryption or scrambling.... more Abstract-The art of security of voice communication in what is known as encryption or scrambling. The main attraction of this method arises from the fact that it can be used with the existing satellite and mobile communication systems without the use of a modem, ...

faculty.kfupm.edu.sa

Abstract-The art of security of voice communication in what is known as encryption or scrambling.... more Abstract-The art of security of voice communication in what is known as encryption or scrambling. The main attraction of this method arises from the fact that it can be used with the existing satellite and mobile communication systems without the use of a modem, ...

The FFT speech encryption algorithm is tested on speech samples which are recorded using a data a... more The FFT speech encryption algorithm is tested on speech samples which are recorded using a data acquisition system connected to a PC. The speech samples are read from an input file by the simulation program and the scrambling operation performed on them frame-by-frame. The scrambled speech signal is output through the filter card and the DAC card. The scrambled speech

A precise, linear indication of the depth of water in a specific part of the sea is required. Thi... more A precise, linear indication of the depth of water in a specific part of the sea is required. This demands a continuous level measurement. There are a wide variety of ways to produce a signal that tracks the depth of water in a specific part of the sea. Ultrasonic detectors find the distance between the seabed and the surface of the water. To measure the level, depth, with an ultrasonic range detector, the module is mounted at the bottom of the sea, seabed, looking up the surface. We must measure the time between the transmit pulse and the echo received pulses. Since the ultrasonic signal is traveling at the speed of sound, the time between transmission and echo received is a measure of the distance to the surface, water depth. A micro-controller sends a pulse to the ultrasonic module. The module transmits an ultrasonic wave for a short period of time and waits to receive its echo. As soon as the echo is received at the ultrasonic module, a pulse is sent to the micro-controller, which measures the time between two pulses. There are two modes of operation, program mode and run mode. When the unit is powered, it is programmed to start up in the run mode, to detect the distance from the transducer face to a target depth in meters. The unit can be placed into program mode at any time by pressing the menu key to alter the value of the parameters in order to better suit the application or user preferences. The unit of measurement, type of measurement, set point of alarms and factory setting are some of its parameters. The working time of the transition and receiver part of the module is specified by the micro-controller normally for each second that ultrasonic pulses are transmitted. The measuring error is approximately 1.25%. Such an error value is acceptable.

Filtration Industry Analyst, 2000

This paper deals with the permutation of FFT (Fast Fourier Transform) coefficients in a speech en... more This paper deals with the permutation of FFT (Fast Fourier Transform) coefficients in a speech encryption system. The scrambling algorithm is based on the permutation of the FFT coefficients and provides a highly secured scrambled signal by permuting a large number of those coefficients. The algorithm for the generation the permutation matrices is explained. This system is useful for a band limited telephone channel and mobile communication. Choice and construction of permutation matrices in the scrambling system are considered. Simulation has been carried out by using the C programming language. The results of simulation and tests show that the proposed scrambling achieves extremely high-level security as well as high speech quality

Mathematical Problems in Engineering, 2009

In this paper, we have presented a new permutation-substitution image encryption architecture usi... more In this paper, we have presented a new permutation-substitution image encryption architecture using chaotic maps and Tompkins-Paige algorithm. The proposed encryption system includes two major parts, chaotic pixels permutation and chaotic pixels substitution. A logistic map is used to generate a bit sequence, which is used to generate pseudorandom numbers in Tompkins-Paige algorithm, in 2D permutation phase. Pixel substitution phase includes two process, the tent pseudorandom image TPRI generator and modulo addition operation. All parts of the proposed chaotic encryption system are simulated. Uniformity of the histogram of the proposed encrypted image is justified using the chi-square test, which is less than χ 2 255, 0.05 . The vertical, horizontal, and diagonal correlation coefficients, as well as their average and RMS values for the proposed encrypted image are calculated that is about 13% less than previous researches. To quantify the difference between the encrypted image and the corresponding plain-image, three measures are used. These are MAE, NPCR, and UACI, which are improved in our proposed system considerably. NPCR of our proposed system is exactly the ideal value of this criterion. The key space of our proposed method is large enough to protect the system against any Brute-force and statistical attacks.

This paper describes an encryption system for analog signals based on permutation of samples. The... more This paper describes an encryption system for analog signals based on permutation of samples. The scrambling algorithm is based on the permutation of the samples and provides highly secured scrambled signal by permuting a large number of those samples. The algorithm for generation the permutation matrices is explained. Important items to be considered in designing the system are discussed such as choice and construction of permutation matrices, and configuration of the practical scrambling system. C programming language was used for simulation. The results of simulation and tests shows that proposed scrambling achieve extremely high-level security. The method of choice and generation of permutation matrices, Tompkin-Paig algorithm and maximum length shift register are discussed. Simulations of different parts of the system, include scrambler, descrambler and generation of permutation matrices programs are provided. Miscellaneous methods of objective tests are described. Theoretical and simulation results of these tests are also provided.

Telecommunication Systems, 2011

We proposed an algorithm to encrypt an image in hybrid domain, frequency and time domains. The pr... more We proposed an algorithm to encrypt an image in hybrid domain, frequency and time domains. The proposed method is a private key encryption system with two main units, chaotic phase-magnitude transformation unit and chaotic pixel substitution unit. Chaotic phase-magnitude transformation unit works in frequency domain and a 2-D DFT is performed on the plain image to change the domain. A chaotic function, the tent map, is used to generate the pseudo random image, which are combined with the plain image in frequency domain. Chaotic pixel substitution unit works in time domain Bernoulli map is applied to produce another pseudo random image that is mixing with the encrypted image nonlinearly. The performance of the proposed chaotic image encryption system is analysed using a computer simulation. The distribution of histogram of encrypted image is uniform. Chi-square value for encrypted image of our proposed method is considerably low. The MSE of the proposed encrypted image is big enough. The correlation coefficients of the proposed encrypted image in all three directions are sufficiently small. The total key length is large enough to resist the proposed system against any brute-force attack. The proposed scheme is robust against chosen plaintext attacks too. The proposed chaotic image encryption system, which is used frequency and time domain together, is more secure than most of single domain image encryption systems.

Proceedings First International IEEE Symposium Intelligent Systems

This paper describes an encryption system for analog signals based on permutation of samples. The... more This paper describes an encryption system for analog signals based on permutation of samples. The scrambling algorithm is based on the permutation of the samples and provides highly secured scrambled signal by permuting a large number of those samples. The algorithm for generation the permutation matrices is explained. Important items to be considered in designing the system are discussed such as choice and construction of permutation matrices, and configuration of the practical scrambling system. C programming language was used for simulation. The results of simulation and tests shows that proposed scrambling achieve extremely high-level security. The method of choice and generation of permutation matrices, Tompkin-Paig algorithm and maximum length shift register are discussed. Simulations of different parts of the system, include scrambler, descrambler and generation of permutation matrices programs are provided. Miscellaneous methods of objective tests are described. Theoretical and simulation results of these tests are also provided.

IETE Journal of Research, 2013

ABSTRACT In this paper, a random bit sequence generator based on chaotic maps is introduced and i... more ABSTRACT In this paper, a random bit sequence generator based on chaotic maps is introduced and implemented. In this generator, two chaotic map functions with two different keys are used. The Bifurcation diagram is used to calculate the initial state of the chaotic maps in order to produce the output random bit sequence. Chaotic Logistic and Tent maps classically are defined in an analogue space. In order to implement these chaotic maps on a hardware digital platform, these chaotic maps are modified. Digital chaotic Logistic and Tent maps are introduced. A design for implementation of these modified chaotic maps is also presented. The output bits of two chaotic maps are EX-ORed to produce a random sequence of 1 000 000 bits. These designs are implemented on Field Programmable Gate Array, and the results are reported. The proposed designs are tested by producing 100 samples of 1 000 000 bits, and they pass the standard Federal Information Processing Standard 140-1 and National Institute of Standards and Technology statistical tests for random bit generators.

Arabian Journal for Science and Engineering, 2014

The paper proposes an algorithm for image encryption using the random bit sequence generator and ... more The paper proposes an algorithm for image encryption using the random bit sequence generator and based on chaotic maps. Chaotic Logistic and Tent maps are used to generate required random bit sequences. Pixels of the plain image are permuted using these chaotic functions, and then the image is partitioned into eight bit map planes. In each plane, bits are permuted and substituted according to random bit and random number matrices; these matrices are the products of those functions. The pixels and bit maps permutation stage are based on a chaotic random Ergodic matrix. This chaotic encryption method produces encrypted image whose performance is evaluated using chi-square test, correlation coefficient, number of pixel of change rate (NPCR), unified average changing intensity (UACI), and key space. The histogram of encrypted image is approximated by a uniform distribution with low chi-square factor. Horizontal, vertical, and diagonal correlation coefficients of two adjacent pixels of encrypted image are calculated. These factors are improved compared to other proposed methods. The NPCR and UACI values of encrypted image are also calculated. The result shows that a swift change in the original image will cause a significant change in the ciphered image. Total key space for the proposed method is (2 ∧ 2,160), which is large enough to protect the proposed encryption image against any bruteforce attack.

faculty.kfupm.edu.sa

Abstract-The art of security of voice communication in what is known as encryption or scrambling.... more Abstract-The art of security of voice communication in what is known as encryption or scrambling. The main attraction of this method arises from the fact that it can be used with the existing satellite and mobile communication systems without the use of a modem, ...

faculty.kfupm.edu.sa

Abstract-The art of security of voice communication in what is known as encryption or scrambling.... more Abstract-The art of security of voice communication in what is known as encryption or scrambling. The main attraction of this method arises from the fact that it can be used with the existing satellite and mobile communication systems without the use of a modem, ...

The FFT speech encryption algorithm is tested on speech samples which are recorded using a data a... more The FFT speech encryption algorithm is tested on speech samples which are recorded using a data acquisition system connected to a PC. The speech samples are read from an input file by the simulation program and the scrambling operation performed on them frame-by-frame. The scrambled speech signal is output through the filter card and the DAC card. The scrambled speech

A precise, linear indication of the depth of water in a specific part of the sea is required. Thi... more A precise, linear indication of the depth of water in a specific part of the sea is required. This demands a continuous level measurement. There are a wide variety of ways to produce a signal that tracks the depth of water in a specific part of the sea. Ultrasonic detectors find the distance between the seabed and the surface of the water. To measure the level, depth, with an ultrasonic range detector, the module is mounted at the bottom of the sea, seabed, looking up the surface. We must measure the time between the transmit pulse and the echo received pulses. Since the ultrasonic signal is traveling at the speed of sound, the time between transmission and echo received is a measure of the distance to the surface, water depth. A micro-controller sends a pulse to the ultrasonic module. The module transmits an ultrasonic wave for a short period of time and waits to receive its echo. As soon as the echo is received at the ultrasonic module, a pulse is sent to the micro-controller, which measures the time between two pulses. There are two modes of operation, program mode and run mode. When the unit is powered, it is programmed to start up in the run mode, to detect the distance from the transducer face to a target depth in meters. The unit can be placed into program mode at any time by pressing the menu key to alter the value of the parameters in order to better suit the application or user preferences. The unit of measurement, type of measurement, set point of alarms and factory setting are some of its parameters. The working time of the transition and receiver part of the module is specified by the micro-controller normally for each second that ultrasonic pulses are transmitted. The measuring error is approximately 1.25%. Such an error value is acceptable.

Filtration Industry Analyst, 2000

This paper deals with the permutation of FFT (Fast Fourier Transform) coefficients in a speech en... more This paper deals with the permutation of FFT (Fast Fourier Transform) coefficients in a speech encryption system. The scrambling algorithm is based on the permutation of the FFT coefficients and provides a highly secured scrambled signal by permuting a large number of those coefficients. The algorithm for the generation the permutation matrices is explained. This system is useful for a band limited telephone channel and mobile communication. Choice and construction of permutation matrices in the scrambling system are considered. Simulation has been carried out by using the C programming language. The results of simulation and tests show that the proposed scrambling achieves extremely high-level security as well as high speech quality

Mathematical Problems in Engineering, 2009

In this paper, we have presented a new permutation-substitution image encryption architecture usi... more In this paper, we have presented a new permutation-substitution image encryption architecture using chaotic maps and Tompkins-Paige algorithm. The proposed encryption system includes two major parts, chaotic pixels permutation and chaotic pixels substitution. A logistic map is used to generate a bit sequence, which is used to generate pseudorandom numbers in Tompkins-Paige algorithm, in 2D permutation phase. Pixel substitution phase includes two process, the tent pseudorandom image TPRI generator and modulo addition operation. All parts of the proposed chaotic encryption system are simulated. Uniformity of the histogram of the proposed encrypted image is justified using the chi-square test, which is less than χ 2 255, 0.05 . The vertical, horizontal, and diagonal correlation coefficients, as well as their average and RMS values for the proposed encrypted image are calculated that is about 13% less than previous researches. To quantify the difference between the encrypted image and the corresponding plain-image, three measures are used. These are MAE, NPCR, and UACI, which are improved in our proposed system considerably. NPCR of our proposed system is exactly the ideal value of this criterion. The key space of our proposed method is large enough to protect the system against any Brute-force and statistical attacks.

This paper describes an encryption system for analog signals based on permutation of samples. The... more This paper describes an encryption system for analog signals based on permutation of samples. The scrambling algorithm is based on the permutation of the samples and provides highly secured scrambled signal by permuting a large number of those samples. The algorithm for generation the permutation matrices is explained. Important items to be considered in designing the system are discussed such as choice and construction of permutation matrices, and configuration of the practical scrambling system. C programming language was used for simulation. The results of simulation and tests shows that proposed scrambling achieve extremely high-level security. The method of choice and generation of permutation matrices, Tompkin-Paig algorithm and maximum length shift register are discussed. Simulations of different parts of the system, include scrambler, descrambler and generation of permutation matrices programs are provided. Miscellaneous methods of objective tests are described. Theoretical and simulation results of these tests are also provided.

Telecommunication Systems, 2011

We proposed an algorithm to encrypt an image in hybrid domain, frequency and time domains. The pr... more We proposed an algorithm to encrypt an image in hybrid domain, frequency and time domains. The proposed method is a private key encryption system with two main units, chaotic phase-magnitude transformation unit and chaotic pixel substitution unit. Chaotic phase-magnitude transformation unit works in frequency domain and a 2-D DFT is performed on the plain image to change the domain. A chaotic function, the tent map, is used to generate the pseudo random image, which are combined with the plain image in frequency domain. Chaotic pixel substitution unit works in time domain Bernoulli map is applied to produce another pseudo random image that is mixing with the encrypted image nonlinearly. The performance of the proposed chaotic image encryption system is analysed using a computer simulation. The distribution of histogram of encrypted image is uniform. Chi-square value for encrypted image of our proposed method is considerably low. The MSE of the proposed encrypted image is big enough. The correlation coefficients of the proposed encrypted image in all three directions are sufficiently small. The total key length is large enough to resist the proposed system against any brute-force attack. The proposed scheme is robust against chosen plaintext attacks too. The proposed chaotic image encryption system, which is used frequency and time domain together, is more secure than most of single domain image encryption systems.