Justice K.S.Puttaswamy(Retd) vs Union Of India on 26 September, 2018 Section 4 of Aadhaar lays down the properties of an Aadhaar number. Sub-section (3) of Section 4 reads as under: (3) An Aadhaar number, in physical or electronic form subject to authentication and other conditions, as may be specified by regulations, may be accepted as proof of identity of the Aadhaar number holder for any purpose. The requesting entities are at liberty to use any or multiple of authentication mode available under Regulation 4 of Aadhaar (Authentication) Regulation, 2016 as per their requirements and needs of security etc. (b) The biometric authentication is based on a probabilistic match of the biometric captured during authentication and the record stored with CIDR. Ans.: Biometric authentication is based on 1:1 matching and, therefore, in that sense it is not probabilistic. If biometrics are captured it will lead to successful authentication. If biometrics are not well captured during authentication or an impostor tries authentication, it will lead to authentication failure. Aadhaar Proof of Concept studies show that a vast majority of residents (>98%) can successfully authenticate using biometric modalities such fingerprints and/or iris. However, the Aadhaar Act and Regulations provides that an Aadhaar number holder cannot be denied service due to the failure of Aadhaar authentication. Hence, all Aadhaar applications must implement exception processes. Possible methods to implement the exception process include: (i) Family Based Authentication: Family based applications such as PDS or Health applications may allow authentication by family members to allow resident to avail services. (ii) Alternate Modalities: Some applications may use different modalities for exception handling. Alternate modalities include: (a) Iris Authentication (b) OTP Authentication (if allowed by policy) (iii) Biometric Fusion: UIDAI is introducing face authentication as secondary authentication factor to reduce the rate of authentication failures, especially for senior citizens. At this time, face authentication will be used only conjunction with another authentication factor such as finger/iris/OTP. (a) Face + Finger Fusion (b) Face + Iris Fusion (c) Face + OTP Fusion Indian Kanoon - http://indiankanoon.org/doc/127517806/ 36