Biometric traits are permanently associated with a user. Though this is an advantage from identity verification point of view, if such biometric data is compromised, it cannot be replaced by a new one and becomes unusable in the system. This limitation can be overcome by combining biometrics with cryptographic techniques to induce revocability in biometric systems. In this paper, a multi-biometrics based cryptographic key regeneration scheme is proposed which combines information from iris and face to obtain a long cryptographic key having high entropy. The biometric information fusion is carried in feature domain using weighted feature level fusion technique. With the proposed system, we obtain 210-bit keys with 183-bit entropy (which is significantly higher than the 83-bit entropy obtained for iris), at a False Acceptance Rate of 0% and a False Rejection Rate of 0.91%