Output Feedback Mode Research Articles

Evaluation and Analysis of Interferograms from an InSAR Radar Encrypted by an AES-Based Cryptosystem with The Five Encryption Modes

This paper falls within the framework of the security of satellite images, in particular interferograms from an Interferometric Synthetic Aperture Radar (inSAR) system. The innovation of this work consists in the application of a cryptosystem based on two algorithms Advanced Encryption Standard (AES) and the Rivest, Shamir and Adleman (RSA) encryption algorithm for securing interferograms of inSAR systems. AES employs five encryption modes Electronic Code Book (ECB), Cipher Bloc Chaining (CBC), Cipher FeedBack (CFB), Output FeedBack (OFB), and counter-mode encryption (CTR). The use of the AES algorithm alone can only ensure the confidentiality function. In the proposed cryptosystem confidentiality is ensured by the AES algorithm, authenticity is guaranteed by the RSA algorithm, and integrity is ensured by two parameters; the correlation function between the adjacent pixels and the SSIM parameters (structural similarity index SSIM). For evaluation and analysis of security performance for interferogram encryption, several test metrics are employed. These metrics are: Analysis of histograms of the encrypted interferograms, correlation between the adjacent pixels, between the original interferogram and the encrypted interferogram, SSIM between the original interferogram and the decrypted one. Moreover, we exploit the analysis of resistance to error propagation for the five modes. The obtained results show a superiority of the OFB and CTR modes for the encryption of inSAR interferograms compared to ECB, CFB, and CBC modes. It is noteworthy, that the main criteria that can be used to choose between OFB and CTR for encryption of satellite images are propagation of errors and the complexity material for their locations on the edges of the satellites propagation of errors and the complexity material for their locations on the edges of the satellites. OFB mode is employed in satellites to minimize the number of on-board circuits, which is decisive for satellites. CTR mode is recommended by the CCSDS (Consultative Committee for Space Data Systems) for telemetry (TM) and remote control (TC) encryption.

Number of Pixel Change Rate and Unified Average Changing Intensity for Sensitivity Analysis of Encrypted inSAR Interferogram

The transmission of images from satellites to earth is on the brink of many threats which can affect the confidentiality of the data as well as its quality. Several encryption algorithms are used to secure the transmitted images. The objective in this work is to analyze the sensitivity of a particular type of satellite image, which is an interferogram from interferometric imaging systems inSAR system. This image is encrypted by cryptosystem based on the Advanced Encryption Standard with key length of 256 bits (AES-256) standard and the asymmetric Rivest, Shamir & Adelman (RSA) encryption algorithm using Counter-mode encryption (CTR) mode and Output FeedBack (OFB) mode. The analysis made in this paper is carried out on two types of sensitivity. The first analysis is the sensitivity to change of a pixel in the original interferogram and the second is the sensitivity to the key. Two parameters are used to assess sensitivity: The Number of Pixel Change Rate (NPCR) and the Unified Average Changing Intensity (UACI). The obtained results show that the two modes AES-256-OFB and AES-256-CTR are favorable but cannot be implemented on board a satellite without providing a mechanism capable of compensating for the low resistance to error propagation. Metrics on the clear and encrypted interferogram are exploited such as the Structural Similarity Index (SSIM), Gradient-based Structural Similarity (GSSIM), The use of these metrics, allowed us to see that a change of one pixel in the interferogram and the change of the encryption key will affect the quality of the interferogram, as well as a statistical histogram analysis.

Efficient chaotic-based image cryptosystem with different modes of operation

This paper proposes a design of 2-D chaotic Baker map for image encryption which utilizes three modes of operations: 1) the cipher block chaining (CBC) mode, 2) the cipher feedback (CFB) mode, and 3) the output feedback (OFB) mode. The proposed image cryptosystem is characterized by a short encryption time of scalevariant images and a high level of confusion and diffusion due to its shuffling and substitution processes. This is useful in applications such as online streaming of paid videos, in which both the speed of encryption\decryption and a good encryption quality is required. A comparison between the proposed image cryptosystem, the traditional 2-D chaotic Baker map permutation cryptosystem, and the RC6 substitution cryptosystem is presented in the paper. A comparison is held with relevant techniques and the results reveal that the proposed image cryptosystem achieves a high degree of security. It is also more immune to noise than the RC6 cryptosystem and takes less processing time for images with large dimensions than both the chaotic cryptosystem and the RC6 cryptosystem. The superiority of the proposed cryptosystem has been proved for image encryption against the recent techniques from the cryptographic viewpoint.

Efficiently Encrypting Color Images With Few Details Based on RC6 and Different Operation Modes for Cybersecurity Applications

Recently, massive research works have been accomplished for augmenting privacy and security requirements for cybersecurity applications in wireless communication networks. This is attributed to the fact that conventional security processes are not appropriate for robust, efficient, and reliable multimedia streaming over unsecure media. Therefore, this paper presents an efficient color image cryptosystem based on RC6 with different modes of operation. The proposed cryptosystem is composed of two phases: encryption and decryption. The encryption phase starts by decomposing the color plainimage with few details into its RGB components, which in turn, are segmented into 128-bit blocks. These blocks are then enciphered using RC6 with an appropriate mode of operation. After that, the corresponding enciphered blocks of RGB components are multiplexed for constructing the final cipherimage. This scenario is reversed in the decryption phase. The performance of the proposed cryptosystem is gauged via simulation using a set of encryption quality metrics. The simulation results reveal that the proposed cryptosystem with cipher block chaining (CBC), cipher feedback (CFB), and output feedback (OFB) modes can efficiently and effectively hide all information of the color images with few details even in the presence of some input blocks with similar data. On the other hand, the results show that the electronic codebook (ECB) mode is not effective at all in hiding all details of images. Finally, the obtained results ensure the applicability of the proposed cryptosystem and its efficiency in encrypting images in terms of security, encryption quality, and noise immunity.

Efficient Chaotic Encryption Scheme with OFB Mode

Data confidentiality is mandatory during transmission or when storing sensitive information, especially in financial, medical and military applications. In this context, several cipher solutions and techniques have been presented in the literature. However, existing solutions are mainly based on static structures, where the confusion and diffusion primitives are fixed and independent of the secret key. In this article, we propose a new block cipher scheme that is based on the Substitution Permutation Networks (SPN). The proposed cipher consists of three operations: round-key addition, substitution, and bits’ permutation. Moreover, the substitution operation is applied at the byte level and it is based on a dynamically generated S-box, while the diffusion primitives are applied at the bit level using a dynamically generated P-box. Such key-dependent design ensures better cryptographic strength and system performance when compared, for instance, to DES, 3DES, RC5, and PRESENT schemes, among others, due to its key expansion algorithm. Thorough analysis show that the proposed scheme exhibits a high degree of randomness, key and plain-text sensitivity, and it satisfies the avalanche effect. From a theoretical perspective, we have formulated the Output Feedback mode of operation as a discrete dynamical system on a topological space. We prove that the dynamics of this system (in terms of sensitivity to the initial vector, etc.) are directly related to the strong connectivity of a graph. By doing so, we are able to characterize the conditions under which this mode evolves chaotically, as defined in Devaney’s theory. In particular, such theoretical investigations allow us to link the avalanche effect and key sensitivity of the cipher with the sensitivity of the whole process, that is, with the mode of operation.

Joint Crypto-Stego Scheme for Enhanced Image Protection With Nearest-Centroid Clustering

Owing to the exceptional growth of information exchange over open communication channels within the public Internet, confidential transmission of information has become a vital current concern for organizations and individuals. In the proposed content-protection scheme, the decryption key is embedded in the encrypted image by utilizing machine learning, nearest-centroid clustering classifier, followed by least significant bit matching (LSB-M) in the spatial domain. An image is first encrypted with the advanced encryption standard (AES) algorithm in output feedback mode, after which the AES key is embedded into the encrypted image. Preliminary nearest-centroid clustering followed by shuffling the sequence of pixels within the clusters before applying LSB-M makes any attack more complex, as the bits of the key are further dispersed within the encrypted image. In terms of contributions, one contribution is the direct implementation of the proposed security mechanism on color images rather than first converting them into gray tones. Another contribution of the Crypto-Stego method is that, it requires no separate key distribution mechanism to decrypt the information. In addition, a parallel-processing approach is implemented to improve the execution time and the efficiency of the scheme by exploiting system resources. Extensive experiments were performed on RGB images with different resolutions and sizes to confirm the effectiveness of the scheme. The high structural similarity index score confirmed that the overall carrier image and stego-image were unaltered by processing. While an average value over the test images of 0.0594 for mean squared error confirmed that malicious individuals cannot detect the presence of stego data in the cover image. Moreover, negligible pixel intensity histogram changes also validated the effectiveness of the proposed scheme. An average 77% efficiency and 1.5 times speed-up factor were achieved through parallel processing showed the effectiveness of the joint Crypto-Stego method for image confidentiality.

FPGA Implementation and Analysis of the Block Cipher Mode Architectures for the PRESENT Light Weight Encryption Algorithm

Objective: This paper presents the Field Programmable Gate Array (FPGA) implementations of the different block cipher mode architectures of the ISO standardized light weight block cipher PRESENT, designed for resource constrained devices. Methods/ Statistical Analysis: The performance evaluations compare the implementations of the different block cipher modes, namely Electronic Code Book (ECB) mode, Cipher Block Chaining (CBC) mode, Cipher Feedback Mode (CFB), Output Feed Back Mode (OFB) and CounTeR (CTR) mode for the PRESENT cipher. The throughput of encryption of three successive 64 bit blocks of data ranges from 565.312Mbps to 574.784Mbps for the modes other than the cipher feedback mode in the Spartan-3 FPGA. The throughput for providing confidentiality through encryption in the cipher feedback mode arrives as 68.912 Mbps, 155.392Mbps and 300.8 Mbps for a 64 bit block of data for the input streams of size 8 bits, 16 bits and 32 bits respectively. Findings: The throughput of the block cipher mode hardware architectures of the light weight cipher PRESENT demonstrates the high speed performance of the cipher in encryption/decryption of data as blocks and streams. Application/ Improvement: The significance of the proposed work is to know the hardware performance of the different modes of operation for the light weight block cipher PRESENT. The performance estimation of the block cipher modes operations of the PRESENT cipher definition in hardware have been carried out for the first time.

Automated Proofs of Block Cipher Modes of Operation

We present a Hoare logic for proving semantic security and determining exact security bounds of a block cipher mode of operation. We propose a simple yet expressive programming language to specify encryption modes, semantic functions for each command (statement) in the language, an assertion language that allows to state predicates and axioms, and rules to propagate the predicates through the commands of a program. We also provide heuristics for finding loop invariants that are necessary for the application of our rule on for-loops. This enables us to prove the security of protocols that take arbitrary length messages as input. We implemented a prototype that uses this logic to automatically prove the security of block cipher modes of operation. This prototype can prove the security of many standard modes of operation, such as Cipher Block Chaining (CBC), Cipher FeedBack mode (CFB), Output FeedBack (OFB), and CounTeR mode (CTR).

Output Feedback and Single-Phase Sliding Mode Control for Complex Interconnected Systems

This paper generalized a new sliding mode control (SMC) without reaching phase to solve two important problems in the stability of complex interconnected systems: (1) a decentralized controller that uses only output variables directly and (2) the stability of complex interconnected systems ensured for all time. A new sliding surface is firstly designed to construct a single-phase SMC in which the desired motion is determined from the initial time instant. A new lemma is secondly established for the controller design using only output variables. The proposed single-phase SMC and the decentralized output feedback controller ensure the robust stability of complex interconnected systems from the beginning to the end. One of the key features of the single phase SMC scheme is that reaching time, which is required in most of the existing two phases of SMC approaches to stabilize the interconnected systems, is removed. Finally, a numerical example is used to demonstrate the efficacy of the method.

Substitution cipher based on pseudo non-determined gamma generator

Substitution ciphers replace symbols or other parts of the plaintext to ciphertext similar parts. Ciphers using cryptographic gamma have high security level, but a significant disadvantage is the high complexity of the operations and, consequently, much lower speed encryption versus ciphers based overlay gamma. This paper is dedicated to developed information ciphering method using gamma generator which considers the secret key and the open message. The obtained results allow increasing the ciphering speed compared with the block ciphers in ciphertext feedback and output feedback modes, meanwhile providing the cryptographic persistence which is comparable with the block ciphers persistence

CMOS Security-Enhanced Passive (SEP) Tag Supporting to Mutual Authentication

A new cryptographic suite (CS) for mutual authentication is proposed on the basis of the next Electronic Product Code Class-1 Generation-2 (C1G2) standard. The Advanced Encryption Standard cryptographic algorithm with a block size of 128-b is used, and a modified output-feedback mode is applied for generating a key, encrypting data, and decrypting data. As a result, the proposed mutual authentication has fast processing speed. To install this CS into the CMOS passive tag, several low-power design techniques are utilized for the digital processor. The fully integrated CMOS security-enhanced passive (SEP) tag is designed and implemented with the Tower 0.18- μm CMOS process. Regardless of secure level on radio-frequency-identification communications, the CMOS SEP tag intercommunicates with the SEP interrogator emulator under a long identification range. In the measured results, the CMOS SEP tag has sensitivities of -12.0 and - 11.6-dBm in insecure and secure communications, respectively. Moreover, it takes a short time of around 40 ms to mutually authenticate a couple of tag and interrogator. Therefore, it is expected to take roughly 1 s for mutual authentications between 25 tags and 1 interrogator.

Increase Security in DS/CDMA UWB using Hybrid Method of CDMA

ULTRA-WIDEBAND (UWB) is a new technology that provides high data rate and low power consumption. The physical layer built in of DS/CDMA UWB is provided by short pulses of nanosecond, the low output power and the absence of carrier signal. CDMA methods are considered as the main proposed method in this paper by integrating cryptographic techniques into the transceiver design. The two main methods that used in enhancement physical layer of CDMA are proposed to be used in DS/CDMA UWB in this paper. The first one is hidden direct sequence for encrypting spreading code. The second one is secure scrambling method at chip rate, which is based on Advanced Encryption Standard (AES) and Output Feedback Mode (OFB). The hybrid method is found much stronger than using anyone of the above method individually.

A Novel Structure with Dynamic Operation Mode for Symmetric-Key Block Ciphers

Modern Internet protocols support several modes of operation in encryption tasks for data confidentiality to keep up with varied environments and provide the various choices, such as multi-mode IPSec support. To begin with we will provide a brief background on the modes of operation for symmetric-key block ciphers. Different block cipher modes of operation have distinct characteristics. For example, the cipher block chaining (CBC) mode is suitable for operating environments that require self-synchronizing capabilities, and the output feedback (OFB) mode requires encryption modules only. When using symmetric-key block cipher algorithms such as the Advanced Encryption Standard (AES), users performing information encryption often encounter difficulties selecting a suitable mode of operation. This paper describes a structure for analyzing the block operation mode combination. This unified operation structure (UOS) combines existing common and popular block modes of operation. UOS does multi-mode of operation with most existing popular symmetric-key block ciphers and do not only consist of encryption mode such as electronic codebook (ECB) mode, cipher block chaining (CBC) mode, cipher feedback (CFB) mode and output feedback (OFB) mode, that provides confidentiality but also message authentication mode such as the cipher block chaining message authentication code (CBC-MAC) in cryptography. In Cloud Computing, information exchange frequently via the Internet and on-demand. This research provides an overview and information useful for approaching low-resource hardware implementation, which is proper to ubiquitous computing devices such as a sensor mote or an RFID tag. The use of the method is discussed and an example is given. This provides a common solution for multimode and this is very suitable for ubiquitous computing with several resources and environments. This study indicates a more effectively organized structure for symmetric-key block ciphers to improve their application scenarios. We can get that it is flexible in modern communication applications.

Audio Encryption in Hand sets

A novel method to encrypt audio(sound) stream of data by applying chaos is discussed. A pair of one-dimensional logistic maps is used for generating a chaotic sequence. The routine tests of encryption are performed and the results are observed. The proposed scheme is then implemented in real time on a mobile phone and the robustness of the idea is established. Index Terms — chaotic System, cipher-block chaining (CBC) mode , Mean squared error (MSE), Peak signal to noise ratio, cryptography, Audio encryption & Output Feedback Mode

Efficient Tweakable Enciphering Schemes From (Block-Wise) Universal Hash Functions

This paper describes several constructions of tweakable strong pseudorandom permutations (SPRPs) built from different modes of operations of a block cipher and suitable universal hash functions. For the electronic codebook (ECB) mode based construction, an invertible blockwise universal hash function is required. We simplify an earlier construction of such a function described by Naor and Reingold. The other modes of operations considered are the output feedback (OFB) mode and a counter-like mode. All the constructions make the same number of block cipher calls and the same number of multiplications. Combined with a class of polynomials defined by Bernstein, the new constructions provide the currently best known algorithms for the important practical problem of disk encryption.

Testing Image Encryption by Output Feedback (OFB)

When it is necessary to securely transmit data in open networks, the encryption must be performed. Most of the cryptographic algorithms were mainly developed for text data. Unfortunately, algorithms those are good for textual data might not suitable for image. The OFB mode of encryption implemented to test five images of different resources, by using three combinations (schemes): a combination of an 8-bit input block with an 8-bit feedback block, a combination of an 8-bit input block with a 16-bit, or a combination of a 16-bit input block with a 16-bit feedback block. Results showed that higher degree of encryption achieved when the input block and the feedback block are of the same size. The OFB mode achieved a mid range level of encryption with a mean entropy value of 7.93.

Research on End-to-End Encryption of TETRA

The Terrestrial Trunked Radio ( TETRA) system uses end-to-end encryption in addition to the air interface encryption to provide enhanced security. The TETRA system uses a synchronization technique known as frame stealing to provide synchronization of end-to-end encrypted data. However, the frame stealing process degrades the quality of video. This paper proposes an end-to-end encryption system with the frame stealing technique for voice and frame insertion for video. A block cipher in the output feedback mode is used to implement the end-to-end key stream generator. Moreover. In the Short Data Service ( SDS) message encryption, a block cipher in the Cipher Block Chaining ( CBC) mode is used to calculate the cryptographically secure checksum, which is sufficient to certify the integrity.

Survey and benchmark of block ciphers for wireless sensor networks

Cryptographic algorithms play an important role in the security architecture of wireless sensor networks (WSNs). Choosing the most storage- and energy-efficient block cipher is essential, due to the facts that these networks are meant to operate without human intervention for a long period of time with little energy supply, and that available storage is scarce on these sensor nodes. However, to our knowledge, no systematic work has been done in this area so far. We construct an evaluation framework in which we first identify the candidates of block ciphers suitable for WSNs, based on existing literature and authoritative recommendations. For evaluating and assessing these candidates, we not only consider the security properties but also the storage- and energy-efficiency of the candidates. Finally, based on the evaluation results, we select the most suitable ciphers for WSNs, namely Skipjack, MISTY1, and Rijndael, depending on the combination of available memory and required security (energy efficiency being implicit). In terms of operation mode, we recommend Output Feedback Mode for pairwise links but Cipher Block Chaining for group communications.

Generic architecture and semiconductor intellectual property cores for advanced encryption standard cryptography

A generic architecture for implementing the advanced encryption standard (AES) encryption algorithm in silicon is proposed. This allows the instantiation of a wide range of chip specifications, with these taking the form of semiconductor intellectual property (IP) cores. Cores implemented from this architecture can perform both encryption and decryption and support four modes of operation: (i) electronic codebook mode; (ii) output feedback mode; (iii) cipher block chaining mode; and (iv) ciphertext feedback mode. Chip designs can also be generated to cover all three AES key lengths, namely 128 bits, 192 bits and 256 bits. On-the-fly generation of the round keys required during decryption is also possible. The general, flexible and multi-functional nature of the approach described contrasts with previous designs which, to date, have been focused on specific implementations. The presented ideas are demonstrated by implementation in FPGA technology. However, the architecture and IP cores derived from this are easily migratable to other silicon technologies including ASIC and PLD and are capable of covering a wide range of modern communication systems cryptographic requirements. Moreover, the designs produced have a gate count and throughput comparable with or better than the previous one-off solutions.

Output feedback variable structure control design

This paper describes a procedure for variable structure output feedback control (VSOFC) for a class of multivariable linear time-invariant systems. The equivalent control method of Utkin in the output feedback mode yields a reduced-order system exhibiting output feedback equivalent dynamics. Using the Kimura-Davison sufficient conditions for pole-placement using output feedback, a sufficient condition is derived to assign the eigenvalues of the 'reduced'-order system. The observability and controllability of the reduced system is discussed. Two switching surface design algorithms are introduced based on both a static output feedback and on an eigenstructure assignment techniques. A control design is discussed as well.