Sharing Privacy Protected and Statistically Sound Clinical Research Data Using Outsourced Data Storage

Table 7

Complexity analysis of our SCDA system.

	Computation cost	Communication cost
Preparation.	𝑂(𝗇ℋ)· CSA.Key + 𝑂(𝗇ℛ)· GHV∗.Key	⋅
Data Publication.	𝑂(𝗇𝖢⋅𝗇ℋ⋅𝗇𝖳)· CSA.Enc	𝑂(𝗇𝖢⋅𝗇ℋ⋅𝗇𝖳⋅|𝐜|)
Query.	⋅	⋅
Aggregation.	𝑂(ℐ⋅𝑠)· GHV∗.Add	𝑂(ℐ⋅𝑠⋅|𝐜|)
Consent.	𝑂(ℐ)   · CSA.reAgg	𝑂(ℐ⋅|𝐜|)
Acquisition.	𝑂(1)· GHV∗.Dec	⋅

Let 𝗇_ℋ be the number of hospitals, 𝗇_ℛ the number of researchers, 𝗇_𝖢 the number of numeric clinical data attributes, 𝗇_𝖳 an average of the number of tuples owned in the 𝑖th hospital ℋ_𝑖, ℐ the number of hospitals such that the 𝑗th researcher ℛ_𝑗 is interested, 𝑠 an average of the number of tuples in the 𝑖th hospital ℋ_𝑖 such that the 𝑗th researcher ℛ_𝑗 is interested, and |𝐜| the size of a ciphertext in the GHV∗ homomorphic encryption scheme.