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Sachdeva E.,YMCA University of Science and Technology | Mishra S.P.,Scientific Analysis Group
Proceedings of 2015 IEEE International Conference on Electrical, Computer and Communication Technologies, ICECCT 2015 | Year: 2015

Extraction of cryptographic keys, passwords and other sensitive information from the memory, has been made possible by the data remanence property of DRAM. According to it, DRAM can retain its data for several seconds to minutes without power [1]. Cold boot attack proposed in [1] tries to exploit memory remanence property, for extracting probable cryptographic secrets from DRAM. However, extracted information is degraded and needs to be corrected before being used for decrypting the encrypted files. Various methods for correcting this distorted data for different cryptosystems have been proposed [1, 6]. However, it has not been reported much in literature regarding efficacy of these methods. This paper contains results and observations of extensive experiments carried out for correcting AES keys, by varying timings of cold rebooting the PC that varies the % of distorted data. These observations suggest that the proposed methods are theoretical in nature and not effective practically( for cold boot attack) as they could correct keys corresponding to up to 2% of erroneous round key schedules of AES-128 and AES-256. In this paper, an improved algorithm has been proposed for correcting up to 15% of errors in cold boot attack generated as well as randomly generated distorted round key schedules. The proposed algorithm has been successfully implemented to mount the volumes encrypted by popular disk encryption system 'TrueCrypt'. © 2015 IEEE.

Walia G.S.,Scientific Analysis Group | Kapoor R.,Delhi Technological University
Proceedings of the 2013 3rd IEEE International Advance Computing Conference, IACC 2013 | Year: 2013

The aim of this paper is to propose an algorithm for particle filter which will overcome its problem of particle impoverishment. Our approach embed cuckoo search via levy flight algorithm into standard particle filter for Non-linear and Non-Gaussian state estimation. The use of cuckoo search via levy flight optimization overcomes the problem of particle impoverishment which is generated during resampling. To validate the efficacy of the proposed algorithm, its performance is compared with the particle filter and PSO Particle Filter (PSO-PF). Simulation results for generic one dimensional problem and two dimensional classic bearing only tracking problem show that our novel Cuckoo-PF outperforms other algorithms when RMSE, robustness and sample impoverishment are considered as metric for performance measurement. © 2013 IEEE.

Verma S.,Scientific Analysis Group | Pal S.K.,Scientific Analysis Group | Muttoo S.K.,University of Delhi
Souvenir of the 2014 IEEE International Advance Computing Conference, IACC 2014 | Year: 2014

Theft or loss of a mobile device could be an information security risk as it can result in loss of con fidential personal data. Traditional cryptographic algorithms are not suitable for resource constrained and handheld devices. In this paper, we have developed an efficient and user friendly tool called 'NCRYPT' on Android platform. 'NCRYPT' application is used to secure the data at rest on Android thus making it inaccessible to unauthorized users. It is based on lightweight encryption scheme i.e. Hummingbird-2. The application provides secure storage by making use of password based authentication so that an adversary cannot access the confidential data stored on the mobile device. The cryptographic key is derived through the password based key generation method PBKDF2 from the standard SUN JCE cryptographic provider. Various tools for encryption are available in the market which are based on AES or DES encryption schemes. Ihe reported tool is based on Hummingbird-2 and is faster than most of the other existing schemes. It is also resistant to most of attacks applicable to Block and Stream Ciphers. Hummingbird-2 has been coded in C language and embedded in Android platform with the help of JNI (Java Native Interface) for faster execution. This application provides choice for en crypting the entire data on SD card or selective files on the smart phone and protect p ersonal or confidential information available in such devices. © 2014 IEEE.

Dhall S.,University of Delhi | Pal S.K.,Scientific Analysis Group
ITNG2010 - 7th International Conference on Information Technology: New Generations | Year: 2010

In today's digital world, encryption has become a prerequisite for many applications requiring data transfer over open and insecure networks. In addition, the advent and fast evolution of mobile technologies has facilitated the need for lightweight encryption schemes which prove to be strong as well as computationally less expensive than the present day standard ciphers. With this as the source of motivation, the paper proposes a new 128-bit block cipher using 128-bit key and performs 8 rounds of operations. Flexibility in the design paves way for extending the block size as well as the key size. The basic strength of the scheme is the conditional processing and the use of non-linear operations during key expansion to generate round keys and the encryption process. Use of simple negation, shift, XOR and substitution operations makes the scheme computationally efficient and less expensive for high bandwidth applications. Results obtained for different types of inputs show almost equal distribution of 0's and 1's in the cipher. Also, change in the cipher with one bit change in the key or plain text is also drastic and depicts strict avalanche effect. Results indicate the strength of the scheme which is also computationally cheaper than many other standard block ciphers. © 2010 IEEE.

Bajaj R.,University of Delhi | Bedi P.,University of Delhi | Pal S.K.,Scientific Analysis Group
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

Steganography is an art of hiding information in such a way that prevents the detection of hidden messages. Besides security of data, the quantity of data that can be hidden in a single cover medium, is also very important. We present a secure data hiding scheme with high embedding capacity for messages of variable length based on Particle Swarm Optimization. This technique gives the best pixel positions in the cover image, which can be used to hide the secret data. In the proposed scheme, k bits of the secret message are substituted into k least significant bits of the image pixel, where k varies from 1 to 4 depending on the message length. The proposed scheme is tested and results compared with simple LSB substitution, uniform 4-bit LSB hiding (with PSO) for the test images Nature, Baboon, Lena and Kitty. The experimental study confirms that the proposed method achieves high data hiding capacity and maintains imperceptibility and minimizes the distortion between the cover image and the obtained stego image. © 2010 Springer-Verlag.

Ghorpade S.R.,Indian Institute of Technology Bombay | Hasan S.U.,Indian Institute of Technology Bombay | Hasan S.U.,Scientific Analysis Group | Kumari M.,Scientific Analysis Group
Designs, Codes, and Cryptography | Year: 2011

Using the structure of Singer cycles in general linear groups, we prove that a conjecture of Zeng et al. (Word-Oriented Feedback Shift Register: σ-LFSR, 2007) holds in the affirmative in a special case, and outline a plausible approach to prove it in the general case. This conjecture is about the number of primitive σ-LFSRs of a given order over a finite field, and it generalizes a known formula for the number of primitive LFSRs, which, in turn, is the number of primitive polynomials of a given degree over a finite field. Moreover, this conjecture is intimately related to an open question of Niederreiter (Finite Fields Appl 1:3-30, 1995) on the enumeration of splitting subspaces of a given dimension. © 2010 Springer Science+Business Media, LLC.

Luthra J.,Netaji Subhas Institute of Technology | Pal S.K.,Scientific Analysis Group
Proceedings of the 2011 World Congress on Information and Communication Technologies, WICT 2011 | Year: 2011

The monoalphabetic substitution cipher encrypts a given text by replacing every letter in the text with a different letter according to some predefined scheme. The cryptanalysis of this cipher involves the identification of this scheme using known language statistical data. The firefly algorithm (FA) is a metaheuristic algorithm, inspired by the flashing behavior of fireflies. This paper discusses the integration of the operators of mutation and crossover commonly used in Genetic Algorithms with the Firefly Algorithm for cryptanalysis of the monoalphabetic substitution cipher. © 2011 IEEE.

Ratan R.,Scientific Analysis Group
Advances in Intelligent and Soft Computing | Year: 2012

Privacy of information is an important issue in modern era of information technology to manage handling of sensitive information over networks efficiently. It is seen that individual use of inversion and circular shifting while encryption of images does not provide adequate security and weaknesses remain can be exploited by interceptors. In this paper, we propose an improved encryption scheme which utilizes both inversion and shifting in specific manner. We use pseudo random number sequences to perform inversion and circular shifting in a random manner for transforming image pixels. Simulation results show that encrypted images obtained are quite unintelligible and pixels distributed uniformly. Also, proposed encryption method is error propagating, follows avalanche criteria, has large key space and provides higher information security. © 2012 Springer India Pvt. Ltd.

Ratan R.,Scientific Analysis Group
Advances in Intelligent Systems and Computing | Year: 2014

Cryptology deals with the design and analysis of secure communication and information management systems. Cryptography protects vital information from adversaries by the process of encryption and cryptanalysis provides adversaries information being communicated by exploiting cryptographic weaknesses. Cryptography is the key technology which is used in various information security applications to achieve security solutions such as confidentiality, authenticity, integrity, availability and non repudiation. Nature inspired computing applied successfully in various artificial intelligence and pattern recognition problems of various fields gives an inspiration to apply in cryptology. Evolutionary computing is being applied nowadays to achieve solutions of cryptographic and cryptanalytic problems. In this paper, we present brief on cryptosystem and overview on applications of genetic algorithms in cryptology. Findings show that the work on nature inspired computing in cryptology is minimal but the applications of genetic algorithms are increasing. The genetic algorithms are not only applied on less complex and classical ciphers but some block ciphers are also attempted for their solutions. Further insight research is needed to tackle various problems of modern cryptography using genetic or other evolutionary computing techniques. © Springer India 2014.

Ratan R.,Scientific Analysis Group
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

Cryptographically, an encryption algorithm should be strong enough so that one could not extract any information from encrypted data. A graphical encryption method proposed in [1] for the security of computer data is cryptanalysed in this paper. There are some regions left unchanged and clearly visible in graphically encrypted images. Key independent decryption of graphically encrypted images is proposed for recovery of intelligible information. Decryption scheme is based on neighbourhood similarity characteristics of adjacent pixels. Simulation results show that the decrypted images obtained by the proposed scheme are quite intelligible to understand. The graphical encryption method in present form is not suitable for security applications as encrypted images can be decrypted easily. © 2010 Springer-Verlag.

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