In biometric based authentication, biometric traits of a person are matched against his/her stored biometric profile and access is granted if there is sufficient match. However, there are other access scenarios, which require participation of multiple previously registered users for a successful authentication or to get an access
grant for a certain entity. For instance, there are cryptographic constructs generally known as secret sharing schemes, where a secret is split into shares and distributed amongst participants in such a way that it is reconstructed/revealed only when the necessary number of share holders come together. The revealed secret can then
be used for encryption or authentication (if the revealed key is verified against the previously registered value). In this work we propose a method for the biometric based secret sharing. Instead of splitting a secret amongst participants, as is done in cryptography, a single biometric construct is created using the biometric traits of the participants. During authentication, a valid cryptographic key is released out of the construct when the required number of genuine participants present their biometric traits.© (2006) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.