In the traditional cryptosystems, secret keys are perfectly hidden for any possible attackers and only the cryptographic algorithms and public parameters are public. However, in practical applications, the attacker can obtain partial information about the matched decryption key from the noise channels or by the side-channel attacks. This study proposes a leakage-resilient hierarchical wildcard pattern encryption in which a user is associated with a wildcard identity pattern. A secret key is derived for a vector of identity strings where entries can be left blank using a wildcard, and this key can then be used to derive keys for any pattern that replaces wildcards with concrete identities. The scheme supports the wildcard pattern key delegation, which is considered as a general extension of leakage-resilient hierarchical IBE (identity-based encryption) and HVE (hidden vector encryption). Moreover, the proposed scheme can tolerate partial key leakage, and the scheme is proven to be leakage-resilient and semantically secure in the standard model under the subgroup decision assumptions.
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