Efficient Two-Step Protocol and Its Discriminative Feature Selections in Secure Similar Document Detection

Algorithm 7

Modification of Line of SSDD-FS to implement SSDD-HF.

(1-0) Obtain through SecureDF.

(1-1) and are -dimensional document vectors.

(1-2) Alice normalizes and to and by using Eq. (5).

(1-3) Alice obtains the difference vector from and by .

(1-4) Alice chooses dimensions, , whose values are larger than the other dimensions.

(1-5) Alice sends those indexes to Bob. // This can be done together with Line of Algorithm 1

(1-6) and are -dimensional feature vectors extracted from and by using those

   indexes. // , , .