From: Ciphertext-policy attribute-based encryption with hidden sensitive policy from keyword search techniques in smart city
Leaf nodes of \(\widehat{{\mathcal {T}}_2}\)
Hash value of the index of the corresponding attribute
\(y_1\)
\(H_{j_1}\)
\(\vdots\)
\(y_t\)
\(H_{j_t}\)