PPSEB: A Postquantum Public-Key Searchable Encryption Scheme on Blockchain for E-Healthcare Scenarios

Algorithm 1

.

Input: security parameter k, discrete Gaussian Distribution , security Gaussian Distribution , .
Output: The set
(1)	Select one uniform vector randomly
(2)	Assume that and compute and
(3)	Set these two hash functions: and
(4)	Call TrapGen(q,n) algorithm to generate and , where and are public key and secret key of patient, respectively
(5)	Call TrapGen(q,n) algorithm to generate and , where and are public key and secret key of doctor, respectively
(6)	Return the set