Abstract
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We propose a new Ciphertext Policy Attribute Based En-
cryption (CP-ABE) scheme where access structures are de-
ned by AND-Gates with wildcards. One major dierence
between our scheme and the existing ones is that we can
use a single element to represent one attribute, while the
previous schemes require three dierent elements to repre-
sent the three possible values (namely positive, negative,
and wildcard) of an attribute. Our proposed scheme also
achieves both constant-size ciphertext and constant num-
ber of decryption operations, and is proven secure under the
standard Decision Linear Assumption.