The use of biometrics for access control on hand-held devices such as smartphones and tablets is in common use now. The security of biometrics and privacy of users’ data has become more important in this scenario. The templates stored in the database or a network are prone to different attacks. Since, biometrics are unique to an individual, their loss imparts the loss of privacy and identity. Unlike passwords, biometrics once lost or stolen cannot be recovered. Cancelable biometrics is one way to address these issues. In cancelable biometrics, pseudo-identities are used in place of original biometric identities and multiple pseudo-identities can be generated for an individual. These pseudo-identities are supposed to be non-invertible and attackers can not extract original biometric from pseudo-identities. If one pseudo-identity is compromised in any way, another pseudo-identity can be issued. This way cancelable biometrics can provide privacy and security to biometrics.
This dissertation proposes three methods for generating cancelable biometric templates. Contributions have been made for transformations at feature level and also for extracting and compressing features. Two contributions have been made for feature level transformations using Binary Coding and Random Projection (RP). These techniques not only meet the requirements of performance, security, and privacy for many modalities but are also capable of dimension reduction without using any predefined dimension reduction algorithms. Rigorous experimentations have been performed for evaluating these methods on various datasets of modalities such as Face Near Infrared (NIR), Palm Print, Palm Vein, Dorsal Vein, Wrist Vein, and Knuckle Print. The evaluation of these methods has been done in three different scenarios for addressing different uses and attacks possible.
Convolutional AutoEncoders (CAEs) are a great tool for extracting features from images and compressing them to a lower dimension called latent space. Latent space is generated from the input images by extracting the relevant and the most useful features required for approximating the images. In the proposed work, a CAE is used for feature extraction.Extracted features are used for generating cancelable template using Random Salting and Random Convolution. The architecture has been trained for Palm Print, Palm Vein, and Wrist Vein images combined from different datasets namely, CASIA, PolyU, and CIEPUT. The proposed method has been rigorously experimented and evaluated for these modalities. The same evaluation protocol is used for evaluating this method too.