transform function application_number US 20839005 A description biometrics such as fingerprint face and voice offers means of reliable personal identification however unlike passwords and personal identification numbers pins that can be reset or replaced when compromised when a biometric such as the image of a face is stolen it is compromised forever and possibly across multiple systems a cancelable biometric template may be obtained by transforming data obtained from the regular features using a non invertible transform e g as shown in fig1 where biometric data b t is extracted from a biometric b and submitted to a one way transform h to obtain transformed data b th which is stored in a system data base db when verification of identity is to be made data b t e is obtained by extraction from the same biometric b and again submitted to the same transform function h to obtain comparative transformed information b th e which is compared to stored transformed information b th in a matching module using a comparison function m to compare the two sets of transformed data to determine identity match the most commonly used non invertible transform is a one way hash function hashing techniques are frequently used in password based systems in this approach the password itself is not stored in the database instead the password is hashed using a transform function h and the resulting obfuscated text is stored however in approaches in the prior art a password or other information required for the conversion is stored for use i e all information for using the transform function t e g hashing function h is stored in the database and the system is thus.