Space-Efficient Key-Policy Attribute-Based Encryption from Lattices and Two-Dimensional Attributes

Table 2

The comparison between our scheme and related KP-ABE schemes.

	Reference [16]	Reference [17]	Ours
size
size
size
Ciphertext size
Privacy preserving	No	No	Yes
Attribute space	Bounded	Bounded	Unbounded

, , , and . : the maximum number of system attributes in [16, 17]. : the maximum number of system attribute labels in our scheme. : the number of user attributes. : the number of ciphertext attributes. Note that and