development of efficient methods for biometric cryptosystems

Abstract

Biometric systems make use of physical and behavioural characteristics of newlineindividuals for their authentication as these attributes are uniquely associated with newlinethem. For ensuring secrecy and authenticity of classified data, Cryptography is used newlinewherein encryption and decryption of data is done using secret cryptographic keys. newlineThus, a major concern here is to maintain the confidentiality of secret key used for newlinesecuring information. This issue can effectively be addressed by using Biometric newlineCryptosystems which combine biometrics and cryptography in order to utilize the newlinebest of both domains. Cryptography ensures higher level of security, whereas newlinebiometrics provides authentication and non-repudiation. newlineSeveral biometric cryptosystems based on different modalities have been proposed newlineand developed in the past but these systems suffer from various problems. One major newlineproblem is related to unimodal biometric system in which a single biometric newlinecharacteristic is used for authentication. In such systems, the noise which may creep newlinein during data acquisition process, may lower down the performance of the system. newlineAnother issue is related to binding the secret key used in a cryptosystem to newlinebiometrics of the user. Third important challenge is protection of the biometric newlinetemplates stored in the database because if these templates get compromised either newlinethrough some deterministic method or brute force attack then the user would never newlinebe able to use that biometric feature in future. newlineIn order to address these issues concerning various aspects of biometric newlinecryptosystems, research work has been carried out and several methodologies have newlinebeen developed. In order to resolve the first issue, a hybrid multimodal biometric newline8 newlinesystem which combines multimodal features using graph random walk based cross newlineview diffusion, has been proposed. The inherent problem of biometric template newlineprotection has also been addressed by transforming each biometric feature value newlineusing some pre-defined key features. newlineIn addition to this, a novel biometric cryptosystem has been proposed for securing newlinethe cryptographic key wherein a secret key is bound with biometric data of the user. newlineNew objective functions have been defined for creation of helper data by hiding the newlinesecret key. The helper data is subsequently used to retrieve the key. newlineTo address the third major problem, an innovative scheme, the Random Area and newlinePerimeter Method (RAPM)) has been proposed wherein biometric characteristics of newlinean individual is transformed into random values that are stored as cancelable newlinebiometric templates. newlineThus, by developing these innovative techniques and methods, all major issues have newlinebeen addressed for an efficient biometric cryptosystem. The thesis incorporates the newlinedeveloped methodologies, their performance analysis and security analysis along newlinewith future directions. newline newline