Secure Storage and Retrieval of IoT Data Based on Private Information Retrieval

Algorithm 1

Encryption.

Input:(i) ⊳ The content key for each

(ii) ⊳ The data public key managed by Shamir secret sharing

(iii) ⊳ The data access structure, which will be

implicitly included in the ciphertext

Choose ⊳ The random secrets of each data slice

(2) Choose ⊳ A random encryption exponent

(3) Choose ⊳ A random vector, where

are used to share the random encryption exponent

(4) for   to do

(5) Compute ⊳ is the vector corresponding to the j-th row of

the matrix

(6) end for

(7) Randomly choose

(8) Compute: and

(9) for to do

(10) Compute

(11) Compute and

(12) end for

(13) Compute the ciphertext:

Output:The ciphertext