• leakage resilience;
  • continual leakage;
  • leakage bound;
  • unbounded delegation;
  • provable security


Many attention has been attracted by a new security primitive called leakage-resilient cryptography, which guarantees that the cryptographic system is semantic secure even if the key has been partially leaked, which is due to the side-channel attacks that the part of secret key can be recovered. In this work, we present a leakage-resilient functional encryption that supports unbounded extensible subset delegation, which remains provably secure even if the attacker learns some arbitrary partial information about the secret keys. The proposed scheme provides the tolerance of continual leakage in which both memory leakage and continual leakage are captured, which has many appealing applications because there are multiple secret keys per subset string by periodically refreshing the key. The security relies on the static complex assumptions that are based on the static (bilinear) subgroup decisional problems. Finally, we give the performance evaluation such as the size of public parameters, keys, ciphertexts, leakage bound, and leakage ratio under 80-bit security standard. Copyright © 2013 John Wiley & Sons, Ltd.